LPT: Trust someone not for their passing of a chance to do bad, but for their taking up of an opportunity to do good.

I've seen many people get hurt by someone else they trusted. A lot of the time, their trust in someone was established because they did not take an opportunity to do something bad when vulnerability was present.

Eventually though, they found a chance that was worth taking, and the other person gets betrayed. (Or they snapped and let loose their restraints.)

Though it's not guaranteed, I find it far more safe it trust someone who has taken the time to do good, rather than not do bad. You'll find exceptions for both situations, but it's generally more safe to manifest your trust in others through their good deeds, rather than their lack of bad ones.