I think it's about a girl who got into so many destructive relationships that she couldn't see that this time there was a guy who might of cared if she opened up to him. I think he's saying that to love her he would have to prepare to accept this pain of hers as his own, in a way paying for loving her by knowing the person you care about in this world is so unhappy. There is also an element of guilt to it, he feels bad because he didn't see the real her.
I think it's about a girl who got into so many destructive relationships that she couldn't see that this time there was a guy who might of cared if she opened up to him. I think he's saying that to love her he would have to prepare to accept this pain of hers as his own, in a way paying for loving her by knowing the person you care about in this world is so unhappy. There is also an element of guilt to it, he feels bad because he didn't see the real her.