田舎者にはよくわかりません ぼんやり辺境伯令嬢は、断罪された公爵令息をお持ち帰りする

Cynthia, the daughter of a margrave, grew up carefree in the vast countryside home to the kingdom's best army. One day, while enjoying her usual romantic novels, she attends her first evening party in the royal capital. There, she witnesses the story of a duke's son being condemned by a selfish princess and having his engagement broken off! Seeing a scene straight out of a novel, Cynthia bursts out and blurts out, "Then marry me!" (Source: Kadokawa, translated)