Dareka Kono Joukyou wo Setsumei shite Kudasai!: Keiyaku kara Hajimaru Wedding

Viola is the daughter of a destitute earl from a famine-stricken kingdom. Cersis is the rich, handsome and eligible duke of Rosia. He asks for her hand in marriage, but only as his "contract wife!" Instead of undying affection, he promises her a comfortable life with the freedom to do as she pleases—including having a boyfriend! Read on and watch her embrace life as a "pretend wife!"

(Source: Renta!)