"Sarang bi"

"Love means never to say you're sorry". That's a statement from a korean movie called "Love Story".
I though I'd onderstand someday, but I still havent. Jang Geun Suk said once that it is because "love comes from the heart, and when you two know each other's heart it isn't necessary to say sorry". I think I cant understand those words because I have never loved someone with no feeling regret, or like I'm unuseful, or...
may it wasn't "love", even if it felt that way...
Why does love mean never to say sorry?