Sometimes when photographing a particular look, it's good to focus on the details. In this case the curve of the models back with the necklace backlit from the window sets the necklace off as the focus and "sells" the romance of jewelry. If the item of focus is jewelry, then draw attention to it, whether if it's by focusing on the jewelry alone, by spotlighting the jewelry with light, or by having the model interact with the jewelry to draw focus to that piece.
I am a Warren, MI based headshot, fashion, fantasy, fine art, senior, and portrait photographer. I have photographed the Detroit area and Southeastern Michigan for over 25 years.