[jaimehlers]

Yuna is probably the part of a person that tends to be mean and nasty towards other people. The part that only considers other people objects to be used and discarded. Everyone has one, but it's only a part of the person (usually). It doesn't make the decisions and it only provides part of the rationalization.

I think in this case that there may have been some of that rationalization on Ji-soo's part. She probably didn't consider herself worthy of Jin-young; he would have been like a distant star that she couldn't reach. So I doubt it was as cold and calculated as Yuna is making it out to be, though. And no matter what Yuna said, there is no way a human being could throw their life away for someone they didn't care about. Yuna doesn't, and probably can't understand that. So that means that regardless of how things originally started, Ji-soo did actually come to care for Ji-hoon.