he must know

USAGE SUMMARY

The phrase "he must know" is correct and usable in written English.
You can use it when expressing a strong belief or assumption that someone has knowledge about a particular subject or situation. Example: "Given his experience in the field, he must know how to handle this issue effectively."

✓ Grammatically correct

News & Media

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

He must know me".

The New Yorker

"So he must know".

The New York Times - Magazine

He must know.

The New Yorker

He must know it.

Independent

He must know that.

The Guardian

I figured he must know people.

The New York Times

He must know, then, she thought.

The New Yorker

He must know it's over.

The New York Times - Sports

Privately he must know it.

The Guardian - Sport

He must know this is nonsense.

The Guardian

He must know that from all.

The Guardian - Sport

Expert writing Tips

Best practice

Use "he must know" to express a strong inference or expectation that someone possesses certain information, especially when the context suggests it is reasonable to assume they do.

Common error

Avoid using "he must know" when you lack concrete evidence; it's better to use phrases like "he likely knows" or "he probably knows" to convey a degree of uncertainty.

Linguistic Context

The phrase "he must know" functions as an epistemic modal construction, expressing a strong degree of certainty or logical inference about someone's knowledge. As Ludwig AI confirms, this phrase is grammatically sound and commonly used. The examples show its use in various contexts to indicate a speaker's conviction.

Expression frequency: Very common

Frequent in

News & Media

100%

Less common in

Science

0%

Formal & Business

0%

Wiki

0%

Ludwig's WRAP-UP

In summary, "he must know" is a grammatically correct and very common phrase used to express a strong belief or logical deduction that someone possesses particular knowledge. As Ludwig AI confirms, it's widely used in news and media contexts. While generally neutral in register, it's important to ensure the context supports the strong assertion of certainty. Alternatives like "he probably knows" or "he should be aware" may be more appropriate when the level of certainty is lower.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

he has to know

Changes the modal verb from 'must' to 'has to', indicating a requirement or obligation rather than just a strong likelihood.

he surely knows

Replaces 'must know' with 'surely knows' to emphasize the speaker's certainty.

he probably knows

Uses 'probably' instead of 'must' to suggest a higher likelihood of knowledge, but with less certainty.

he likely knows

Similar to 'probably knows', suggesting a good chance that the person is aware of something.

he is aware

Replaces 'must know' with a more direct statement of awareness, implying knowledge without stating it as a necessity.

he should know

Indicates an expectation or obligation that the person has the knowledge, rather than a strong belief.

it's safe to assume he knows

Adds a layer of hedging, suggesting the knowledge is a reasonable assumption.

he understands

Focuses on comprehension rather than mere awareness of facts.

he is cognizant

A more formal way of saying 'he is aware', suitable for academic or professional contexts.

he is informed

Suggests that the person has received information, rather than necessarily understanding it fully.

FAQs

How can I use "he must know" in a sentence?

You can use "he must know" to express a strong belief that someone has certain information. For example, "Given his experience, "he must know" how to handle this situation."

What are some alternatives to "he must know"?

Alternatives include "he should be aware", "he probably knows", or "he is likely to know", depending on the context and the level of certainty you want to convey.

Is it always appropriate to use "he must know"?

It's most appropriate when you have a reasonable basis for believing the person has the information. If you are unsure, using phrases like "he might know" or "perhaps he knows" might be more suitable.

What's the difference between "he must know" and "he should know"?

"He must know" expresses a strong belief or logical inference, while "he should know" indicates an expectation or obligation that the person possesses the information. The second implies that it is important or necessary for someone to have such awareness, unlike the first one.