We've worked for several years with our middle school kids for them to trust us and know that we care for them, and we are there no matter what. Every week, no matter what the lesson plan is, we try to reinforce it. We have talked about some really "personal" and "heavy" subjects with them, and I think our work has paid off, because they listen to us without getting nervous or embarrassed, and are willing to discuss whatever we're talking about. No one to my knowledge has come to any of us teachers with a bad personal problem, but they know if they need to, we're there and will do whatever we can to help them. I guess after all these words what I'm trying to say that trust, trust, and more trust needs to be achieved.
I agree that trust is a great start. I think it needs to be proven with action and not just words. (I'm sure that's a no-brainer, but I said it anyhow)

They have to know they can trust, not just assume it.