I trust absolutely completely, within the realm that trust seems appropriate. For example, after about the first minute of meeting someone, back when I used to do those Starbucks dates, I'd know whether I'd trust the person not to put a date rape drug in my drink. I'm not saying this was wise or not wise, but once I'd made that determination, I never revisited it. The only reason I would is if the person actually gave me new, affirmative evidence that I needed to worry about that. Does that mean that my trust extended to going home with him? Absolutely not. Complete trust not to drug and kidnap me, no trust at all regarding being alone in his apartment. But when I was ready to trust going home with someone, I did it and didn't second-guess that. (Yes, I did have a safe call because I believe in hedging your bets, but did I ever have an internal feeling that that was necessary? Nope.)
So for me, trust is an ever-widening circle. When he proves trustworthy in one area, then I naturally expand my level of trust to a new one. And trust is pretty much an on/off switch for me. If I trust him with something, I trust him with it. I don't second guess, I don't look for contrary evidence, I don't get all paranoid about that little text tone or why is he not answering the phone - unless there's some reason to. Then the trust is gone anyway.
In my current relationship I find that I am free to extend more and more trust because it has never once been abused.