No you don't. You only have your own judgment that you made either from things you heard about this person, or by what you have seen on the outside of this person. God sees the heart.
Luke 6:44 For every tree is known by his own fruit...........
You are applying the principle incorrectly. She isn't remaining in her sin. She is living with the consequence of a sin that has been forgiven. Why can't YOU forgive her of something she did before she was saved? (not that she needs it, but issues like this are why Christians are considered to be the most unloving bunch of people when we are supposed to be dramatically different!)
Incorrect..he has not gone back to presenting himself as a guy therefore there is not repentance and the sin continues. Issues like this are why liberals have no credibility. It is never loving to leave someone in their sin. Never