How do you say so true in french?

There are a few ways to say "so true" in French, depending on the context and level of formality:

Formal:

* C'est tellement vrai! (This is so true!)

* C'est absolument vrai! (This is absolutely true!)

* C'est parfaitement vrai! (This is perfectly true!)

Informal:

* Trop vrai! (So true!)

* C'est vrai! (That's true!)

* Tout à fait! (Absolutely!)

* Exactement! (Exactly!)

* C'est clair! (That's clear!)

Adding emphasis:

* C'est tellement vrai que... (This is so true that...)

* C'est absolument vrai, c'est incroyable! (This is absolutely true, it's incredible!)

The best choice will depend on the situation and your relationship with the person you're speaking to.