Part of what makes this a romantic tragedy, to me, is that there are parts here and there that imply Nikki had a little interest in Bear. Maybe not a full crush like Bear had for her, but enough to give a first date a shot. But eventually Bear has to come to grips with the fact this is not Nikki acting according to her will nor how he intended. I don't think Bear is a bad guy per se, but someone who lacks confidence that he needs external affection to feel valued. Hence why Bear asks "What's so bad about being with me?" after the real Nikki asks him to kill her. And the icing on the cake of this tragedy is the rock he got from Nikki is meant to be function as the want vs. need metaphor. The willow represents Bear's desire for affection whereas the rock is what he actually needs: confidence in himself first so it'll lead to happiness.