What makes us trust people more than others?

I can only say what makes ME trust some people more than others. When they tell me tons of truth in things, instead of having to tease it out. Then I reverse Engineer situations sometimes. Like who told me what in the past and when? Did they have my interests in mind too? Also, how much of what they said was true, and were they intentionally misleading me? SOme folks tell you straight every time, sometimes more truth than you even want or can handle, trust those people. When there is a war or slavery or something, people's lives often depend on that honesty.