Migawari no Hanayome wa Yandere Ryoushu ni Torawareru

Lara, a nobleman's daughter, was sent to the castle of Lord Walter in the place of her older sister who eloped. Lara expected to be treated cruelly, but for some reason, Walter became intensely attached to her, as if his engagement with her sister had never happened in the first place... An other-world yandere love fantasy!

(Source: Kodansha, translated)