Rosalie Hale is a character from the Twilight book series by Stephenie Meyer. She is one of the adopted "children" of Carlisle and Esme Cullen and the partner of Emmett Cullen. Rosalies transformation into a vampire granted her the strength, beauty, and immortality that allowed her to exact vengeance on those who had wronged her in her human life.
Rosalies power is enhanced beauty, which even surpasses that of a regular vampire. She was "angelically beautiful" as a human, and her transformation enhanced her beauty, making her many times more beautiful than most vampires, to the point where shes labeled as the "most beautiful person in the world". Her musical talent was also enhanced as a result of her transformation.
Its important to note that according to the Twilight Saga: The Official Illustrated Guide, Rosalie Hale/Cullen doesnt possess any quantifiable supernatural power, much like her adopted parents, meaning that she also has no powers at all in the Twilight movies.