There's two things I judge harshly on. The inability for one to admit when they are wrong, and lack of courage to say I'm sorry. That tells me all I need to know. Because we are all wrong at some point. But not all of us are sorry.
Experienced this once. Found out the guy not only held onto his own parachute, but had caught someone else instead and hadn't said so because he "didn't want to hurt me." Glad I broke the bones rather than keep trusting an untrustworthy person.