Akujo ni Shitate Agerareta Hakkou Reijou no Shiawase na Konyaku Haki

When her mother's illness takes a turn for the worse, Lilitia meets her father, the Marquis Castion. With no one else to turn to, she agrees to join the House of Castion and become their political tool in exchange for her mother's medical treatment. But as if relinquishing her freedom weren't enough, the duke's son and her new fiancé Jacob absolutely detests commoners. Years later, Lilitia continues to suffer his torment. Under Jacob's instructions, she must now act the bully towards the baron's daughter at the academy, all to deter suspicion away from their secret relationship, One evening, as Lilitia recovers from her torturous day, a strange, handsome man bursts into her home. Enter Ultio, the thief causing a stir in the kingdom for delivering justice to its corrupt aristocrats. Before he makes his escape, the kind-hearted Lilitia notices his injury and offers to mend his wound. What she didn't expect, was how he proposes to return the favor: Help her end her doomed engagement to Jacob! With the mysterious gentleman thief's aid, perhaps freedom (and romance) for our "villainess" in distress is just around the corner! (Source: MangaPlaza)