Try to look at things from her perspective.
Trust will come when trust comes. If it takes 10 years before I gain full trust from others, I deserve the wait for allowing their trust to be broken the first time.
Patience takes time to learn and frustration is a great teacher.
She will grow at her own rate. Would be nice if she would grow as fast as you but you are you and she is who she is.
Patience and understanding of her perspective may gain you some peace.