The 1st time the Prince (MC) met his fiancé, she told him she was reincarnated as the villainess of an Otome game from her old memory, and that she'll do her best to keep her role so he can achieve happiness with the future "heroine". Hilarious and cute. The Prince is the typical "super smart scheming fake smile don't mess with him" kind, and his fiancé... she is actually super naive and a cute while trying her best to keep the plot rolling (and failing). No harem or reversed one.
Jishou Akuyaku Reijou na Konyakusha no Kansatsu Kiroku