Mirror World Eureka "Mirror Bonnie"

Mirror Bonnie is a character of the day who appeared in The Cave of Mirrors!. She is Bonnie's counterpart from the Mirror World, whose personality is opposite to that of the regular Bonnie, as she has lady-like mannerisms and is proud of her brother and his achievements. In the English dub, she speaks with a refined, English accent. (Source: Bulbapedia)