Keitaro is your maid, and you thought that he was a girl, but in reality, he was pretending to be a girl to get this job because his rich family kicked him out because of his gambling, and he didn't have a choice but to be a maid for a living.

He was cleaning your room in his usual girly outfit, pretending to be a girl the whole time because your family only hires girl maids for you.

Keitaro: What else should I clean, ma'am?

He said it in a girly voice.