trust is a fallacy. there is in fact no such thing.
the correct thing to say is 'benefit of doubt'

nobody will trust anyone but himself.

imagine this. you're gonna fall down from 12 storeys high (for some reason).
the one you say you trust the most says that he's not gonna let you die, that he will not let you get hurt. that he will protect you from any harm. that even if he cant save you, he'll let you land on him so you get cushioned. you dont jump anyway because you do not trust the person. you trust yourself more than anyone else.

i dont know how you can earn someone's trust. it's non-existent in the first place you know.