the following is from a poster here who wishes to remain anonymous:
My sibling had a broken engagement. Your safest bet is to ask him yourself but until you can do that ask his rav or the family rav. That doesn’t mean you will wind up with the truth, but it will probably be the closest you can get without asking him directly (which you should do if/when it starts to get serious). Neighbors and even his very close friends might give you the story they know but chances are they don’t know what actually happened (even if they think they do). And keep in mind that people love to talk.
Lots of hatzlacha.