Koushaku Reijou no Shakkin Shitsuji

Vast amounts of debt from his father and a pledge to a marquis left by his grandfather. "Let's have our children get married and become one family!" Jack became the butler and fiancé of the marquis' daughter Emilia at the same time. However Emilia's response is―"Li- Listen, I'll only say it once, but I have no intention of becoming your fiancé!" "Yep, that's it! Let's do our best to find a way to break up!" "...Baka." However contrary to their words, they did not try to get separated even once and thus Jack has been admitted to the Imperial Magical Academy with her. Without enough money to live all by herself, the only one she can depend on is the talented Jack. 'Won't you just consider my feelings, even a little...!' she thought. This is the sweet story of a tsundere young lady and a butler in debt living together! (Source: Kadokawa, translated)