How can I know that God is or isn't real?

If there is a god then he probably wouldn't let us have 100% proof that he is real, so that we can have faith in him instead of just having physical proof. so we cant know for sure that he is or isn't real. But if there isn't a god, then eventually we should be able to find 100% proof that he isn't real, and that people are just bending reality to fit their religion. but we don't have that proof yet. So, how can I know if he exists or not?