Quora:

Can you trust your partner at the beginning of a relationship?

"No, not really. What you have, at the beginning of a relationship, is a willingness to trust. A willingness to take that risk - but no. You do not actually trust them. Trust is earned, bit by bit, over time.

It isn’t something “big” either … it’s the small things that happen, that show you that this person is trustworthy. And the little things add up, building a history and creating the trust."