you'll tell him/her
You’ll tell him where it hurts.
You will tell him yourself.
J'ai rien à promettre, tu lui diras ce que tu voudras.
I have nothing to promise; tell him whatever you want.
— Tout sur ma mère (1999)
Qu'il commence par t'épouser, tu lui diras après.
Let him marry you first; then you can tell him.
— Moscou ne croit pas aux larmes (1980)
Will you tell him why?
Will you tell him?
Tu lui diras ton admiration plus tard.
You can tell him how much you admire him later.
— Le Pianiste (2002)