no

In a sentence

• Non, je ne veux pas de dessert.

  No, I don't want any dessert.

  Here, 'no' as 'non' is used to directly negate or refuse the proposal of having dessert.

• Je pense que non.

  I think not.

  In this case, 'no' as 'non' is utilized to denote disagreement with a previously discussed topic or idea.

• Ce n'est pas clair, non ?

  It is not clear, isn't it?

  Here, 'no' as 'non' functions at the end of the sentence as a tag question seeking confirmation.