It is hard when one's partner in a relationship is not accepting of our transition.
About all you can do is to keep talking. Take your time. Sometimes, a partner will come around when they see that you are becoming a happier person. Sometimes, they don't.
Remember that she is a unique individual, and has a right to her feelings, whatever they are. That might mean losing her. Or it might mean deciding not to transition. Or you might get lucky and have both.
All you can do is to communicate the best you can, and after that, it is not up to you.