Kawai Sugiru Imouto o Mamoru Tame, Kyouikukakari ni Narimashita

Dedicated to her work, Satoko was reborn as Emilia Frolich, a young woman in a world with strange morals; Wherein women are not permitted to have a will of their own. So, when her younger sister is forced into an arranged marriage with the Crown Prince, she simply accepts it. "This cannot be allowed!" Enraged, Emilia volunteers to be her teacher, giving her the knowledge she needs to fight against this unreasonable world. What will become of her bond with her sister? What will become of her relationship with the Crown Prince Maximilian, whom she once considered her enemy? A romantic fantasy in which a powerful heroine changes the world!