The anime/manga series Shinseki no Ko to Otomari Dakara de na
When put together, the phrase roughly translates to: "Because I’m staying over with my relative’s kid..." The Narrative Trope: The "Sleepover" Scenario
Official Publishers: Following the specific studio's website often provides news on upcoming chapters or episodes.
推定原文 (Possible original):
「親戚の子とお泊まりだから、なーふぇ？」
(Shinseki no ko to o-tomari dakara, nā fe?)