believe in

(phrasal verb) to have confidence in someone or something

Example Sentence:

Son: Dad, I want to be a dancer. Do you think I can do it?
Dad: You’re 250 kilos, clumsy, and have no rhythm, but I believe in you, son! Let’s go sign up for dance lessons!

I can’t decide if I like Obama or Clinton. The only thing I really believe in is democracy!