Learn French: Tu es censé ne pas offenser les invités. - You are supposed not to offend the guests.

The phrase être censé followed by an infinitive expresses an expectation or a theoretical obligation, exactly like "to be supposed to" in English. Because it acts as an adjective, censé must agree in gender and number with the subject. Since it's spelled censé here without an extra "e", we know the tu being addressed is masculine. If you were speaking to a woman, it would be Tu es censée.

Why is it ne pas offenser instead of n'offenser pas?

When negating an infinitive verb in French, both parts of the negation (ne and pas) stay together and are placed directly before the infinitive. Therefore, it is always ne pas offenser (not to offend), never n'offenser pas.

Could I say Tu n'es pas censé offenser les invités instead? Is there a difference?

Yes, you can, but there is a subtle difference in nuance. Tu n'es pas censé offenser negates the expectation ("You are not supposed to offend"), while Tu es censé ne pas offenser directly negates the action ("You are supposed not to offend"). Just like in English, this sentence makes the expectation a bit stronger—it is actively your duty not to do it. However, in everyday conversation, the two are often used interchangeably.

I have seen the word sensé before. Can I spell it Tu es sensé here?