It depends on who it is. If it's someone close to me I'd confront them (whether it was something told to me or I knew 100% to be true) because sometimes what we think to be true or to have happened, isn't always the way it is. (Does that make sense?) Kind of like letting them explain and more times then not you can tell if they're skirting around it or being honest. If it's not someone close to me I more times then not don't give it a 2nd thought.