accepting it. you cant do anything to change whats happened. for me, i accept it whole heartedly, and try and make up for it by bettering not only myself but the person affected and by giving it my all to somehow make up for it.
you made a mistake. but shes fairly young correct? the least you could do, as a guardian and someone who she loves and you love as well is be there for her so she doesn't have to suffer anymore than she already does; and to attempt to give her the world, and make her the happiest person on the planet.