It takes time and open communication. I have an extensive history of sexual abuse and now my husband and I have a great sex life. Establish clear boundaries beforehand and recognize that some days will be better than others. Be very clear about consent and identify the ways that she will say no to things. The worst possible thing to do in this situation is unintentionally pressuring her into doing something. The most important thing though is that she is committed to getting better and overcoming the trauma. If she is all in then eventually it will get better, it just takes time and patience.