I agree that b&w was the only choice for a picture like this. The lighting could not be better and I like the way the hair frames her face. Black top and dark nail polish finalises the setup.
The title of the picture provides a certain angle to look at this picture and now that I do, I get also a sense of vulnerability. In addition, a bit of sadness and perhaps even a touch of insecurity and distrust towards the viewer with her hands kept close to her chest as if reluctant to open herself.
All in all, an excellent picture, me like!