Akuyaku Reijou wa Ouji no Honshou (Dekiai) wo Shiranai

Bertia realized that she had been reincarnated as a villainess in an otome game during a blind date with Prince Dylan. But because she played the knight's storyline in her previous life, she didn't know what the prince's character was like!　 She decided to try her best as the prince's fiancée for the time being, but she was surprised when he kissed her on the cheek every time they met. And then he told her "Stay by my side for the rest of your life"... Is it because of some bug?　

(Source: B's-Log Bunko, translated)