18+ Hitogirai Koushaku wa Wakaki Niizuma ni Koi wo Suru

One day, Minerva's engagement to the Crown Prince is called off. However, she soon got engaged to Duke Mars, the brother of the King. Marriage with the Duke, who is unrivaled in terms of beauty and status, would make anyone envious. However, he is famous for his "misanthropy" and rarely shows up at social gatherings or smiles. What will happen to her marriage with him?

(Source: Harper Collins Japan, translated)