Doukyuusei no Dorei ni Nattemita I Became the Slave to My Classmate.

Synopsis

Yasuomi Takezuka is in deep trouble as his parents' company went bankrupt and his family got into debt! Thankfully, a rich classmate, Sakuranomiya, offers to save his house. However, there's a condition: "From today on, you are my slave." But things are totally not going as Sakuranomiya expected... (Source: Ichijinsha, translated)