Akuyaku Reijou wa Ouji no Honshou (Dekiai) wo Shiranai

At a blind date with Prince Dylan, Bertia suddenly recalled her previous life and realized that she has been reincarnated as a villainess in an otome game. In order to avoid the bad end, she decided to keep her distance from the prince, but to her surprise, he chose her as his fiancée. "I won't let the prince have a sad childhood!" The lonely prince had five more years until he will meet the heroine. So she decided to be his friend and support him until then, even though she was only going to be his temporary fiancée. But as they get to know each other better... the prince's attachment to her became more and more intense! "I will love you no matter what happens." I'm not the heroine, so why is he doting on me...!? (Source: Kadokawa, translated)