One of the worst feelings in the world is when you're deeply in love with every aspect of someone you can not have. Some reasons you can't date them usually are: they're dating someone else, you're too good of friends, they don't see you that way, the list goes on. Since I'm a guy, I only know how it feels for us to be in this situation, although Taylor Swift gives some pretty good insight in the song "You Belong with Me." We hate to see the best friend we're in love with love someone else, we hate them see them treated subpar, we hate to see them not with us. We want them all to ourselves, we're selfish when it comes to them. There is nothing in the world you wouldn't give to be with that person, you know they're the one for you, they just haven't gotten the hint yet.
I have a bestfriend who I would give the world for. She makes me happy with just the little things she does. We love these people in our lives so dearly, but we aren't happy for them... just because they aren't with us. We don't have to think this way. This person was brought into your life to impact your life. Be happy for this person-- they could be in love with you and not even know it. The problem might not be they don't want you, but that they don't know you're who they need.
Be there for them, listen to them crying when their feelings are hurt, protect them, take care of them, don't stop loving them. Be in their corner when they feel like they have no one else. Love is patient, love is kind. There is always the chance this person is your soul mate, they could come around. Don't deny yourself of love while they're out indulging in it. If it is meant to be, it will find a way.
Don't give up, but don't force it on them. It is never easy watching them not be with you, but wait until your timing is perfect.
