KEMEKO DX

The story centers on a typical high school boy and a super-deformed, doll-like robot that suddenly appears in his bedroom. The robot declares itself to be the boy's wife, and only then does a beautiful girl emerge out of the robot's mouth. The girl turns out to be someone who was promised the boy's hand in marriage ten years earlier. (Source: Anime News Network) — Description from AniList community (anilist.co).