Akuyaku Reijou no Keibo wa Ni ga Omoi no de, Zenryoku de Shiawase Route Mezashimasu

Barbara Seitel, the daughter of a count who loves handsome men, was a university student in Japan in her previous life. Due to a freak accident, she was reincarnated into her favorite book, and now, at the age of 18, she has a happy arranged marriage meeting, but who is her partner?! A wicked duke who will (supposedly) plunge the country into the depths of terror in the future!? If I fall in love with him, both myself and my family will be ruined. Even though I know this in my head, the duke's refreshingly handsome personality makes my heart flutter, and I can't stop my excitement from building... Now that it's come to this, is there no other option but to pursue a happy ending with him and his stepdaughter, the future villainess (provisional name), who will commit evil deeds with him?! "I'll show you I can avoid a bad ending!!"