KONYAKU HAKI SARETA NODE OSOUJI MAID NI NATTARA WARAWANAI KIKOUSHI-SAMA NI DEKIAI SAREMASHITA

Mithril, a viscount's daughter, has her engagement broken off because she lacks feminine charm. With the financial support cut off as a result of the broken engagement, Mithril fears that her family's finances may be in jeopardy because of her, so she takes a job as a cleaning maid for the magic corps! Mithril is assigned to the Shisui, a magic corps full of filthy rooms known as the "den of evil." While the other servants show signs of revulsion, Mithril efficiently goes about her work, and Shisui quickly becomes clean. Mithril doesn't try to please anyone and devotes herself wholeheartedly to her work, but the smileless wizard Alfreed aggressively approaches her with sweet words—!? (Source: Futabasha, translated) — Description from AniList community (anilist.co).