They say that time heals all wounds but all it do is give you more time to think about how much you miss that person that broke it... Its actually up to her when she's ready to let go she will its all a matter of choice and unfortunately there's very little you can do, for now you can just be there for her when she needs kleenex or a shoulder to cry or someone to lash out on or drinking buddy
You probably will never be able to do anything for her. The only way she will snap out of it is if she meets someone who is genuinly good to her that she learns to trust. It's like a spell she has to be awakened from by only a special person to her.
time is the only thing that ever works for this. as for what to say, "i'm here for you" is pretty quick and to the point. you don't really need to say anything else. if it's been going on a long time, it's time to start doing. the more stuff to fill her time and her life, the better. keep her busy.
she is lucky to have someone who wants to make her feel happy. I hope she realizes this. Everyone heals in their own time, usually when the right person comes along. Maybe she is not ready for you yet or she is too scared? Help her to trust you, if that is an issue.
I'm afraid that the harsh reality to life on this earth is that in the moment it seems just that-harsh. Feeling as if your heart is broken is by far the harshest life lesson to overcome. Quite frankly, it SUCKS.
Sometimes even just admitting it and giving it a bit of space works. "IT SUCKS." Just saying the truth about it can work. "IT SUCKS!" Stand up right now. Put your arms up and proclaim, "It sucks over and over." I just lost a family member last week and the first thing I thought was, "it sucks!"
Now grab a hug from me. Because as much as our heart breaks, it never leaves us without a place for love.
If her heart doesn't feel, then she's very fortunate. I would think you should just leave her alone.
By deploying a paradox?
It will heal in time, it just doesn't feel like it right now. Cliche I know, but true.
I know it sucks to hear but you just have to wade through it.
Accept that you will soon start to feel better and you will soon start to feel better. Not much better at first but better and then a little better again until one day you will wake up and reaslise you are ok again.
Try to focus on the other people and things in your life that are good and trust me on this; all the good things you think you have lost you will have again with someone new.