How do you say nothing's wrong in french?

Answer 1

nothing's wrong would be translated 'rien n'est faux, rien n'est incorrect'. That gives a double negative and French speakers just say usually 'rien' (when told there's something wrong here...), or use the opposite phrase 'tout VA bien' (all is good).

Answer 2

You can say "Il n'y a rien de mal" to convey the idea of "nothing's wrong" in French.