"Pourquoi tu... et moi" refers to the French title of the anime series (originally Kanojo ga Koushaku-tei ni Itta Riyuu ).
The episode you are looking for, , is titled "Celle qui a été bousculée" (The One Who Was Pushed). In this episode, the plot thickens as Raeliana attends a monster hunt and faces a life-threatening encounter that forces Duke Noah Wynknight to intervene. Pourquoi tu... et moi EP06 Vostfr.mp4
You can find this episode and the rest of the series on official streaming platforms like Crunchyroll, which provides the high-quality version you're looking for. "Pourquoi tu