to serve you; to use
J'espérais pouvoir te servir à quelque chose, moi.
I was hoping I could be of some use to you.
Je ne pourrai pas te servir plus longtemps.
I won't be able to serve you any longer.
— The Legend of Bhagat Singh (2002)
Tu sais te servir d'un micro-ondes ?
Do you know how to use a microwave?
— Les Lundis au soleil (2002)