Over the course of this book, how have Rose and Lissa changed?

Rose and Lissa both have matured. In the end of the story, they are no longer part of the rumor mill, and they don't allow the petty differences to get between their friendship anymore. Rose finally accepts Christian for who he is, and admits that he is good for Lissa. Lissa, despite being denounced by the queen and being the center of the rumor mill, does not let public opinion affect her decisions anymore.