Peten Hakushaku no Kakoware Hime: Taishou Otome Koijutsu Shinan

Momiji, a daughter with dreams of being a swordswoman, has been thrust into an arranged marriage with a prestigious earl she has never met.

Soon after, she agrees to a match with Shuichiro, a senior dojo student, betting that if she loses, he can do whatever he wants with her. But after her defeat, he sweetly claims his prize by taking her virginity?!

Trying to escape this marriage, Momiji ends up falling right into the deceiving earl's trap...!

(Source: Ohzora Shuppan)