613 "Actually…"

Why people talk their confidential story to me? Not only to me of course, but I often find myself being told such stories that goes like this "Actually, I am…", even though I never ask them and never feel inclined to do. It's surprising to me. Once I asked one of my friends, "it's always welcome, but why you feel like talking to me your secret story?" and the answer was whichever it's true or not, "you are reliable." Can I just accept the fact that luckily I am regarded as such person and should be proud of what I am? I've been wondering if there is any other strong reason that people talk their secrets to someone you trust. Sense of alliance? Or it's a way to find solution and peace of mind? That's one of the questions I have for a long time.