_Chickennugget
I mean, if you think about it he approached her, not her approaching him. I don't think she was really trying to flirt with him. She was happy to get some free cake(who wouldn't be) and she was glad there was a kind new someone to talk to her and spend time with her. Humans need interaction, and she's a slave sure but even slaves need attention and love. You gotta feel bad for her because he is jumping to conclusions without talking to her about it because he views her as property.
It would have been better if he did slapped her rather than ripping of her clothes, Ripping off the clothes gives the Trauma which isn't easy to be recover from for a girl. He proved himself that he is not a worthy of love at all, I'm feeling hurt for Rosalie... wish she could do something to save herself.