The Girl Next Door(2017)

Original title: 옆집소녀

Sae-hee couldn't go to sleep from the first day in her new house because of the moaning coming from next door. Sae-hee has never had sex before, but she's writing sex novels. Playboy Seong-hyeon was getting tired of his sex partner Jia when he finds out that Sae-hee is a sex novelist. He begins to help her with her work but really he's using that as bait to get into her pants and he does. Will Sae-hee be able to complete the novel?