You must not smoke. vs You dont have to smoke.

[Edgarlandia]

I had heard it is not correct to say "Must not", because that's why exist "Have to". Is that real or not?

So that's my question, e.g. both sentences are correct?

-You must not smoke

-You dont have to smoke

[Milanya]

"Must not" and "do not have to" have different meanings.

Must not - it is prohibited. You must not drink and drive.

do not have to - it is not necessary. You do not have to go out every night.

You must not smoke - it is bad for your health.
You do not have to smoke to fit in. They will like you anyway.
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con·text - The part of a text or statement that surrounds a particular word or passage and determines its meaning.