In the context of being outcasted and people interactions, I think people trust you if you conform and show that you are one of them, and follow the same rules, like if you drink coffee, watch the popular tv shows and talk about the weather. There are also unspoken rules which need to be followed, like the way you act and facial expressions. Most people may follow a similar pattern of interaction because they are socially calibrated, but someone already outcasted won't know the rules, and they can sense this, that you are an outsider.
When you show you follow the same rules, then people will trust further interactions with you because they can rely on you to react in a certain way. Like if someone dies they would expect you to be sad an cry. But if you are an out of the box thinker and instead are happy for them escaping the suffering of life, you will be outcasted.