I've Been Proposed to by a Villain

I witnessed a murder scene of a villain. To make matters worse, he caught me. I think I hear the sound of death beckoning. He approaches me, his hand in his coat. I wonder what he’s reaching for. A knife? A gun? I guess it doesn’t matter. There’s only one thing I can think of now. “I’m going to die.” I wasn’t expecting what he pulled out of his coat. “Will you marry me?” “What?” --- I witnessed the novel's villain murdering someone - and even got caught witnessing it! I can practically hear the bell signalling the end of my life ringing. However, what he gave me was... "Marry me." A ring. One with a huge gem at that! What's going on here?! Is this not better than dying, My Lady? Let's get married. My newly-wed life with the villainous lead begins now! --- Whisked away into the novel *The Forbidden Fruit of Isotta* and the body of Regina Blois, our female protagonist has the advantage of knowing how her story unfolds - which is that she is to be murdered by Duke Arsene Graroy! Her death moves the story forward and sets up her good friend and protagonist Isotta in a love triangle with the Emperor and the Duke when she tries to uncover the truth behind Regina’s death. Not wanting to be murdered this time around, our new Regina keeps a low profile. She still manages to catch the eye of the Duke, but when he confronts her this time, it seems he's less interested in murdering her and more interested in... marrying her?