Mujikaku Seijo wa Kyou mo Muishiki ni Chikara wo Tarenagasu

The "failed" daughter of a duke, whose appearance and abilities are both mediocre, finds a warm "place she belongs" in an arranged political marriage.

The excellent House of the Duchy of Sanchez has two daughters. The older sister, Flora, is a brilliant and talented holy maiden candidate. The younger sister, Carolina, is a plain and talentless dropout... In such circumstances, Carolina receives a marriage offer from the second prince of the neighbouring country to improve the nations' relations. However, her groom, the prince is rumoured to be savage and cruel. Carolina accepts thinking "If I can be of help," but her life completely changes upon marriage. Contrary to the gossip, she is fairly appraised by both the chivalrous prince and the empress, so she is accepted for herself?!