You asked for brutally honest, so please don't be mad...
First the good: Your painting techinque is very nice. I especially like the hair. The contrast is good and the shape flows nicely with the rest of the piece. It's also framed really well, so no complaints about the composition.
but the anatomy... Not the worst if you don't look too closely, but even from far away, something about the torso is askew. Like the upper and lower part of the body are not in agreement about the pose she's in. By that i mean it seems like the perspectives are different depending on whether you're looking at the top or the bottom. Separately they look fine, but together they look like they belong in an esher painting. The biggest miss though is the neck. Perhaps this too is due to an error of perspective because it looks as though it's being viewed from the side... on both sides. It makes neck look tiny compared to the rest of her body. I'd recommend adding some mass to the left side to straighten it out and make it look the right size, and it seems like it should end a little lower down, which might be why the chest looks too big for the rest of her body, though that may have been a stylistic choice. The only other recommendation i'd make is to suggest that you make the background a color that compliments the colors in the foreground instead of matching them.
Sorry if that was harsh, but if its any consolation, i'm hoping for an equally brutal analysis of our own work, so go to town.