I'm kinda confused. He obviously doesn't love the heroine even in the original route. And he doesn't know what love is either. He's just like a child who had found a new plaything nothing more and nothing less. Due to his lack of emotional relationships, he was tricked by the bird and Miss Heroine by hearing such declaration that no-one has really ever said to him directly i think. So this means that even in the original plot, Prince was kind of still an emotionless android. It's hard to explain but you can feel how his interpretation of love and his feelings towards Miss Heroine is off putting.