Stronger Ways to Express Certainty in English (B2-C1)

Hello, English learners. Welcome to a new lesson. Today, we are going to explore stronger ways to express certainty in English. These useful words, phrases and grammatical structures will help you show that you strongly believe something is true, likely or definite.

Learning different ways to express certainty will help you sound more natural, confident and precise. These expressions are useful in everyday conversation, formal writing and professional communication. They are also particularly valuable for learners preparing for the B2 First or C1 Advanced exam.

Some of the stronger ways to express certainty in this lesson communicate complete confidence, while others allow you to express a firm opinion more cautiously.

You can also read our lesson on ways to express uncertainty in English.

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Common Ways to Express Certainty

Let us begin with some common and stronger ways to express certainty in everyday English.

Certain

Meaning: completely sure that something is true.

Register: Neutral.

• I’m certain that this photograph was taken when I was five years old.
• Sandra felt absolutely certain that she had never seen the man before.

Common patterns

• be certain that
• be certain of something
• be certain to do something

You can strengthen the expression with:

• absolutely certain
• completely certain
• quite certain

Positive

Meaning: completely sure that something is true.

Register: Neutral to informal.

When positive means certain, it is commonly followed by that.

• I’m absolutely positive that I left my keys on the desk.
• I’m positive that the man appeared in the film we watched last week.

This expression is often used when someone questions or doubts what you have said.

• “Are you sure you sent the email?”
• “Yes, I’m positive.”

Sure

Meaning: confident that something is true or will happen.

Register: Neutral and very common.

Sure is one of the most natural ways to express certainty in everyday English.

• I’m sure this tea will help your cold.
• What makes you so sure that this is the correct answer?

Common patterns

• be sure that
• be sure of something
• be sure to do something

Do not confuse be sure to do something with certainty about a prediction.

• Be sure to lock the door.

Here, be sure to means remember to or make certain that you do something.

Definite

Meaning: fixed, clear or certain; not likely to change.

Register: Neutral.

Definite is commonly used to describe plans, decisions, arrangements and answers.

• We have not made any definite plans for the summer.
• The manager gave us a definite answer.

It is usually more natural to say:

• The manager was definite about his decision.

rather than:

• The manager was definite that there would be no meeting.

When introducing a clause, certain or clear is often more natural:

• The manager made it clear that there would be no meeting.

Confident

Meaning: believing strongly that something will happen or that you will succeed.

Register: Neutral.

Confident often describes certainty about a future result, ability or prediction.

• Mark was confident that property prices would fall.
• The police were confident of catching the thief.

Common patterns

• confident that
• confident of doing something
• confident about something

Convinced

Meaning: completely sure that something is true.

Register: Neutral to formal.

When you are convinced, you have formed a strong belief, often after considering evidence or arguments.

• The judge and jury were convinced that the accused was guilty.
• The man ran away, convinced that a dangerous dog was chasing him.

Common patterns

• be convinced that
• be convinced of something

Be careful not to confuse convinced and convincing:

convinced describes how a person feels.

convincing describes something that causes belief.

• I was convinced by his convincing explanation.

No Doubt

Meaning: used to say that something is very likely or certain.

Register: Neutral.

• There is no doubt that we will arrive before midnight.
• She is, without doubt, the most experienced candidate.

Notice the different positions:

• There is no doubt that she is qualified.
• She is without doubt the best person for the position.
• He will no doubt accept the invitation.

The last structure often means very probably, rather than complete certainty.

No Question

Meaning: there is no uncertainty or disagreement.

Register: Informal to neutral.

• Mira is the best candidate—no question about it.
• Her experience makes her the strongest applicant, without question.

Be aware that there is no question of doing something can mean that something is impossible or will not be considered.

• There is no question of postponing the examination.

This means that postponement will not be considered.

Know for a Fact

Meaning: to know that something is definitely true because you have evidence or direct knowledge.

Register: Neutral.

• I know for a fact that Jason did not sleep at home last night.
• John knew for a fact that the building contained dangerous chemicals.

Use this expression carefully. It is a strong claim and suggests that you can prove what you are saying.

• I think she has moved abroad.
• This is an opinion.
• I know for a fact that she has moved abroad.

This suggests you have definite evidence.

Correct Me If I’m Wrong

Meaning: used when you believe something is true but invite the other person to correct you.

Register: Polite and neutral.

This phrase does not express complete certainty. It is a cautious way of checking information that you believe is probably correct.

• Correct me if I’m wrong, but haven’t we arranged to meet at ten?
• Correct me if I’m wrong, but you said the meeting had been cancelled.

It is useful in professional conversations because it sounds less confrontational than:

• You told me the meeting was cancelled.

Unless I’m Mistaken

Meaning: used to show that you believe something is true while allowing for the possibility that you may be wrong.

Register: Neutral to formal.

• Unless I’m mistaken, there was a car park here twenty years ago.
• The payment is due tomorrow, unless I’m mistaken.

This expression is useful when you want to sound confident but polite.

Similar expressions include:

• unless I’m very much mistaken
• if I remember correctly
• as far as I remember
• if I’m not mistaken

Beyond Doubt

Meaning: completely certain and impossible to question.

Register: Formal.

• The evidence proved beyond doubt that the document was false.
• The success of the campaign demonstrated beyond doubt that the public supported the idea.

A very common legal expression is:

beyond reasonable doubt

• In criminal trials, the evidence must normally establish guilt beyond reasonable doubt.

Be careful with the word order:

• The evidence proved beyond doubt that he was innocent.

This is more natural than:

• The evidence proved that he was innocent beyond doubt.

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Stronger Adverbs for Expressing Certainty

Adverbs provide another group of ways to express certainty without introducing a complete phrase.

Certainly

Meaning: definitely; without doubt.

• This is certainly one of the best books I have read this year.
• She will certainly be considered for the position.

In spoken English, certainly can also be used as a polite response:

• “Could you help me with this form?”
• “Certainly.”

Definitely

Meaning: without any doubt.

Register: Neutral and common.

• I will definitely attend the meeting.
• This is definitely the right address.

Word order

Place definitely:

• before most main verbs
• after the verb be
• after the first auxiliary verb
• She definitely knows the answer.
• She is definitely qualified.
• They will definitely arrive on time.

Incorrect: She definitely is qualified.

This is possible when emphasising a contrast, but She is definitely qualified is more natural in ordinary English.

Undoubtedly

Meaning: certainly; without question.

Register: Formal.

• She is undoubtedly one of the most influential writers of her generation.
• The decision will undoubtedly affect local businesses.

This is a useful word for B2 and C1 essays.

Social media has undoubtedly made communication faster, although it has also created new problems.

Clearly

Meaning: in a way that is obvious or easy to understand.

• She clearly understands the problem.
• The company is clearly trying to reduce its costs.

Be careful: clearly expresses the speaker’s interpretation. Other people may not consider the situation equally obvious.

Obviously

Meaning: in a way that is easy to notice or understand.

Register: Neutral, but sometimes too direct.

• He was obviously nervous before the interview.
• The proposal is obviously unsuitable.

Use obviously carefully. It can sound dismissive if the listener does not think the answer is obvious.

Instead of:

• Obviously, you are wrong.

A more diplomatic alternative is:

• It seems clear that there may be a problem with that argument.

Bound to

Meaning: certain or extremely likely to happen.

Register: Neutral.

• You are bound to feel nervous before an important examination.
• The new restaurant is bound to be popular.

Structure

subject + be + bound to + infinitive

• The plan is bound to succeed.

Do not say: The plan is bound that it will succeed.

Sure to and Certain to

Meaning: very likely or certain to happen.

• The film is sure to be a success.
• She is certain to receive several job offers.

Sure to is more conversational, while certain to may sound slightly more formal.

Must for Logical Certainty

We can use must when the available evidence leads us to a strong conclusion.

• You have been travelling all day. You must be exhausted.
• The lights are off, so they must have gone home.

This use of must does not express obligation. It expresses a strong logical deduction.

Compare:

• You must finish the report today.

This is an obligation.

• You worked all night. You must be tired.

This is a deduction.

There Is No Way

Meaning: used to express strong disbelief or certainty that something is impossible.

Register: Informal.

• There is no way he completed all that work by himself.
• There is no way they will accept such a low offer.

This expression is strong and may sound emotional, so it is best suited to informal situations.

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Expressing Different Degrees of Certainty

Not all ways to express certainty communicate exactly the same degree of confidence.

Reasonably certain	I’m fairly sure…, I believe…, It seems clear that…
Strongly certain	I’m certain…, I’m convinced…, I’m positive…
Based on evidence	I know for a fact…, It is clear that…, The evidence shows that…
Strong prediction	It is bound to…, It is sure to…, It is certain to…
Logical conclusion	He must be…, They must have…
Complete certainty	There is no doubt…, Beyond doubt…, Without question…
Cautious certainty	Unless I’m mistaken…, Correct me if I’m wrong, but…

Stronger Ways to Express Certainty in Speaking Exams

In a B2 First or C1 Advanced speaking exam, avoid giving every opinion with I think. Use a wider variety of structures.

• I’m convinced that…
• I firmly believe that…
• There is no doubt that…
• I’m fairly certain that…
• It seems clear to me that…
• I would definitely say that…
• I have no doubt that…
• This is undoubtedly…
• I’m confident that…
• It is almost certain that…

Example

Question: Will technology continue to change the way people work?

There is no doubt that technology will continue to transform the workplace. I’m convinced that many routine tasks will eventually be automated, and remote working is certain to become even more common.

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Ways to Express Certainty in Formal Writing

The following expressions are useful in essays, reports and articles:

• It is clear that…
• There can be no doubt that…
• The evidence clearly shows that…
• It is widely accepted that…
• This undoubtedly demonstrates that…
• It is almost certain that…
• There is strong evidence to suggest that…
• It can confidently be argued that…

Example

• There can be no doubt that access to education has improved in many parts of the world. However, it is equally clear that significant inequalities remain.

Avoid making an unsupported opinion sound like a proven fact.

Instead of: Online learning is undoubtedly better than classroom learning.

A more balanced version is: Online learning undoubtedly offers greater flexibility, although it may not suit every learner.

In My Humble Opinion

Meaning: used to introduce a personal opinion, sometimes politely and sometimes humorously.

Register: Informal, especially online.

The abbreviation IMHO is common in messages, forums and social media.

• In my humble opinion, it is a very sound investment.
• In my humble opinion, the second design is more attractive.

However, this expression does not necessarily show certainty. It mainly marks a statement as a personal opinion.

In formal writing, use:

• in my view
• in my opinion
• from my perspective
• it could be argued that

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Common Mistakes

Incorrect: I’m certain about he will come.

Correct: I’m certain that he will come.

Or: I’m certain about his decision to come.

Incorrect: I’m convinced about that he is right.

Correct: I’m convinced that he is right.

Or: I’m convinced of his innocence.

Incorrect: She is sure for passing the exam.

Correct: She is sure of passing the exam.

Or: She is sure that she will pass the exam.

Incorrect: I know it as a fact.

More natural: I know for a fact that it is true.

Incorrect: It is beyond the doubt.

Correct: It is beyond doubt.

Or: It has been proved beyond reasonable doubt.

Incorrect: He must to be tired.

Correct: He must be tired.

Modal verbs such as must are followed by the infinitive without to.

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Practice: Stronger Ways to Express Certainty

Complete the sentences with a suitable word or expression from the lesson.

1. I know for a __________ that she attended the meeting.
2. There is no __________ that the new building will change the appearance of the town.
3. She is __________ to notice that the document has been altered.
4. I’m absolutely __________ that I turned the oven off.
5. The evidence proved beyond __________ that the painting was a forgery.
6. You have been working since six o’clock. You __________ be exhausted.
7. The team is confident __________ winning the competition.
8. Unless I’m __________, we have already paid this invoice.
9. The new policy will __________ cause some confusion.
10. He is __________ that the company made the correct decision.

Answers: 1. fact, 2. doubt, 3. bound/sure/certain, 4. certain/positive/sure, 5. doubt, 6. must, 7. of, 8. mistaken, 9. undoubtedly/certainly/definitely, 10. convinced/certain/confident

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Final Thoughts

There are many stronger ways to express certainty in English, and choosing the right one will make your speech and writing sound more precise. Use sure, certain and positive in everyday English, and choose convinced, confident and there is no doubt when expressing a stronger belief.

Other ways to express certainty, such as bound to, certain to and must, are useful for predictions and logical conclusions.

Related posts:

• Ways to Express Uncertainty in English 
• Other Ways to Say “I Don’t Know” in English 
• Likely, Bound and Sure To 
• Expressing Probability in English
• Ways to Add Emphasis in English
• Collocations for Expressing Opinions in English 
• How to Express Doubt in English 
• B2 First Speaking 
• C1 Advanced Speaking 

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