In order for someone to earn your trust, you have to give them the benefit of the doubt and trust them first. It's a confusing concept, I know, but it's true.
>>2 It's not possible to be 100% sure that someone is trustworthy. There are so many variables it's impossible to know. Trusting someone is an act of faith. Now, some people have a better Chance of being trustworthy, but you can't know
>>1 anyways, I think it depends on the secret. Also, if this person has been a reliable and caring friend then I say take a chance. You never know what might happen