To me these photos just seem to lack something, and i'm not entirely sure what it is.
Theres nothing that makes them jump out at me, or makes me go wow what a lovely photo.
I think you need to work on a number of things.
1. Separating the subject from the background. Now the backgrounds are OOF, which is a good thing, however, in the first three images there is just to much going on in the background, and that draws the attention away from the subject. The last image is the nicest. If i was you I would have blown that background out even more, shooting at an even wider aperture.
2. Composition. All of the photos in my opinion are just not composed correctly. You are leaving to much negative space above your models head for my liking, and you need to watch for things like cutting half her arm of like in the 3rd photo. Either the arm is there, or its not. Something to think about.
3. Lighting. The lighting seems very flat. I would like to see some more contrast. What seems strange to me is that you are firing a speedlight in to a reflector. A reflector should be used to reflect natural light back on to the model. What you really need is a 3rd person to do that for you.
If I was you I would try this. Forget the speedlight/flash. Get out side. Have you model face away from the sun, so you are shooting directly in to the sun, and then have someone feather the light from the reflector back on to the model. Watch you don't get to close, as this will just cause the skin to blow out, but also watch that you don't get to far away. That is why is best to have a 3rd person there to do this for you.
In regards to the model, I think she is gorgeous, but I don't think you have done her justice in this shoot.
Sorry if this seems like alot of critique, its just what I feel needs to be done to improve these images.
Thanks