If you're saying you know it and she's denying...then she's lying. Don't fall for any such bullsh*t such as her crying or getting mad at you. If you need the answers then make sure you get it and you could always verify the info she gives with her friends. Better still, why don't you ask the ex-guy directly? I know I sound like a dick, but if you're gonna be with someone then you gotta make sure the person comes clean rather than regret later when its too late!