I'm Not Breaking Off the Engagement.

"Ah... Ahhhhhhhhhhh!" The one who's become the Crown Prince's fiancée is the Duke's daughter Serea, but during their first meeting, she screamed and collapsed! Had she remembered something from her previous life? Are you an evil villainess? Am I going to break you if I fool around too much? A me that's programmed to be like that, is so horrible. Isn't that right~ An "event" and those "program settings" have no connection to me though. Let's go back to my place and I'll slowly and sweetly make you fall desperately in love with me! This otome game's villainess is going to follow a harsh path, and will fight to change her fate. (Source: Ichijinsha, translated)