I don't think I can read this anymore. The MC says she'll devote her life to her sibling, but gets so easily swayed by the ML, who is honestly such a fucking shitbag. He's an evil murderer who had the worst possible first impression, and has exactly zero appealing or redeeming qualities. Other authors have managed to write evil, sadistic, brutish, tyrants as interesting, and even give them endearing character traits. But there is absolutely nothing likeable about this ML, and the MC who is swayed by him looks like the biggest, dumbest, flimsiest ass in all of existence.
1/10 stars. That 1 is for the younger sibling, the only half-way decent character.