Ben may have really killed her and others OR Could be she killed herself because of debt and also very hurt by…
That's the fun of this movie, who knows if anything's real! Perhaps she isn't even dead and she travelled somewhere again.
To be honest I think a suicide would be likely, it explains how innocent Ben is during the final scene (he went with Jong Su despite knowing he was suspicious of him) however that still doesn't solve how he has her watch. But that also ties in with Jong Su's perspective, he isn't able to question everything Ben has or hasn't done, if he really killed her or not, because his feelings are so strong for Hae Mi.
Buuuut who knows if the ending scene is real either? Maybe it's a fantasy of Jong Su to get revenge on Ben for 'killing' Hae Mi. I don't think there's a right answer to anything in this film, it's all up to the viewer to determine for themselves what is real and imaginary.
To be honest I think a suicide would be likely, it explains how innocent Ben is during the final scene (he went with Jong Su despite knowing he was suspicious of him) however that still doesn't solve how he has her watch. But that also ties in with Jong Su's perspective, he isn't able to question everything Ben has or hasn't done, if he really killed her or not, because his feelings are so strong for Hae Mi.
Buuuut who knows if the ending scene is real either? Maybe it's a fantasy of Jong Su to get revenge on Ben for 'killing' Hae Mi. I don't think there's a right answer to anything in this film, it's all up to the viewer to determine for themselves what is real and imaginary.