Munou Saijo wa Akujo ni Naritai: Gimai no Migawari de Totsuida Reijou, Koushaku-sama no Dekiai ni Kizukanai

Despite Avril's unique ability, her family has always treated her like a bumbling waste of space. Eventually, her parents force her into a marriage of convenience in her wicked half-sister's stead. Contrary to the rumors, however, the decrepit, lecherous Duke Lanchester turns out to be a gorgeous young man. Of all things, Duke Lanchester wants to marry a villainess for three years before divorcing her. For Avril, this is the perfect opportunity to secure her freedom in the future. Thus, the oddball prodigy must do her best to play the villainess, simultaneously bewildering and charming everyone around her! (Source: Cross Infinite World)