Read manga THE ONE WHO GAVE ME LOVE WAS THE DUKE OF DEATH / 愛をくれたのは死神公爵でした
Inés, a servant of the Count’s family, did not remember her childhood and was oppressed by her “lack of emotions”. Then one day, she married Gilbead Deadrix, who was feared to be “The Duke of Death”. This happens because the Count sent Inés to the Duke’s house instead of his daughter. But the Duke, who was not willing to let her get married, decided to keep Inés in the house until their marriage was decided. Contrary to the terrifying rumors, Inés gradually recovers her emotions when she meets the gentle Duke. Then he realized that he had lost his memory, and that he had hidden abilities.