have faith in (someone or something)
To have confidence in someone or something. I know you'll pass this test—I have faith in you. After being a lawyer for so many years, do you still have faith in the legal system?
have faith in someone
to believe someone; to trust someone to do or be what is claimed. I have faith in you. I know you will try your best. We have faith in you and know you can do the job well.