Ateuma Ouji no Jijo ni Tensei!? Yoshi, Hiroin to Konyaku Haki Nante Sasemasen! Mobu Reijou no Hazunanoni, Nandaka Shuui ga Hadenan Desu ga?

Tina is a maid who remembers that she played a video game that contained this world in her past life. But she's not just any maid... she works under the throwaway character Prince Viself who's fated to die as the kingdom falls into ruin! Now she's on a mission: save the kingdom by ensuring Prince Viself doesn't ruin his engagement. However, things take a turn from what she knows from the game story when all these main characters start taking an interest in her...?!

(Source: MangaPlaza)