His Majesty the Demon King's Housekeeper Vol. 1

Sakura loves when everything is neat, clean, and in its place. She's on the school Beautification Committee and spends every spare moment mopping or dusting to keep things tidy and perfect. When Sakura is transported to a fantasy world, she's immediately flabbergasted by how dirty everything is! The land is under a curse which prohibits cleaning magic, and the residents have really let things go.

Even the demon king's castle is a complete mess. Sakura isn't going to stand for it. She'll put this kingdom in order, even if it means working directly with the intimidatingly attractive demon king himself!