When I look at her facial expression, I see that she is dead or is about to die. I also see her dying as if she were going to fall asleep in bed, and she's also very tired; being under a lot of physical pain can be stressful and tiring. But I also see that she's very much at peace with what she is doing. She's at peace as though she finally got around to taking care of something very important and pressing. Maybe by committing seppuku, she's helping to keep safe or protect someone or some people that she loves. But when I look at the hand that holds the knife to her stomach, I see a determination unto the very bitter end. She could be using one hand because she did the mortal damage and now she's about to die. She may be dressed in white because this is a picture of a righteous and justified moment of seppuku. Maybe she's in a white robe instead of being topless, because this was something that she did honorably.
It would have been nice if you could have used more colors other than white in the background. This was very tastefully done. Nice Work!