She hates me....she still hates me

Why can't I still get over it? She wasn't the nicest person even when we were friends, but it still really hurts me that she hates me still.  After one year.  I don't think he knows how much it hurts me to have his sister hate me so much that she can't even bear to see my face.  It feels like she would rather have me dead then be with her brother.  I care about her because she is important to him.  I don't think she even knows how lucky she is to have a brother that cares about her so much.  I don't know what to do anymore.