hm, Johnny, IÃ‚Â´m not sure, if the word joy is perfect, Remember Ichi, the Killer movie, the guy wanted to be beaten by the girl, cuz it was the only way to FEEL anything. It wasnÃ‚Â´t joy, but more the wish to feel anything… And I would call this masochistic…
Would it be wrong to consider it i this way?
Well in the case here, I would say:
Well Bill loves the Bride in his special way, but he has to kill her, cuz she broke his heart, the heart of a killer.
She decided to take the other guy and to leave the killer/Bill. So he has to do what a killer has to do in this case.
But he felt pain to loose her nevertheless. He killed the only woman he ever has loved. So it was not a sadistic wish to hurt her, but a masochistic thing. He had to follow his rule and to kill. Although it hurted him to loose her.
The way he talked during the shooting makes him to an absolute egoistic guy, IMO.
He kills a pregnant woman and all he did was to talk about is his pain…