So sad (T^T) It's really touching to know that someone can really love the other person even if she/he already know that there's the limit of their time to love each other.
She, with an intention of loving him who has the limited life, promise won't let him go no matter what.
He, who know that his life has a limit, try to let her go because he don't wanna make her sad and cry, because he love her so much.
They both love each other with their own way.
The timeline is different from the manga tough and I'm not finish my reading yet (^_^;) But somehow I prefer the movie, because it's more make sense for me.