Rosalie first appears in Twilight, acting as the sister of Jasper. She is mean to Bella, jealous of her being human, and not wanting Bella to choose a life as a vampire. Rosalie is rather vain, self centered, and wishes to be human and have children, so much so that she would give up her immortality and beauty for it. In New Moon, she mistakenly reports to Edward that Bella is dead after she supposedly commits suicide, though Bella was actually just partaking in the sport of cliff-diving. Edward proceeds to travel to Italy, desiring to have the Volturi kill him. In Eclipse, Rosalie reveals her past to Bella with the hopes that she will choose to stay human. She also joins the fight against a group of savage newborn vampires. In Breaking Dawn, Bella contacts Rosalie after finding out she is pregnant, knowing that Rosalie has always wanted children. She stays by Bella's side throughout the pregnancy, defending her choice to keep the baby. Rosalie acts as a guardian to the child, Renesmee, taking care of her while Bella is going through her transformation into a vampire. When the Volturi plot to destroy Renesmee, Rosalie helps gather vampire nomads to provide evidence that Renesmee isn't a danger.
Rosalie Lillian Hale
Rosalie Lillian Hale is the adopted daughter of Esme and Carlisle, adoptive sister of Edward, Alice, and Jasper, and wife of Emmett. Her physical age is 18, and she was born in 1915 in Rochester, New York, as the daughter of a banker. Rosalie is described as being the most beautiful person in the world, even for a vampire; she is tall, statuesque, and has long, wavy blonde hair. As a human, Rosalie was described as a woman who had beauty, elegance, class, and eyes resembling violets. Royce King II took an interest in her and soon the two became engaged. Rosalie was extremely envious of her good friend Vera and her baby boy and, while on a visit, noticed that she did not share the same relationship with Royce as Vera did with her husband. Dismissing it, Rosalie later walked home and met an intoxicated Royce and his friends. Royce bragged about his fiancée's beauty, leading to her being beaten, presumably raped, and left to die. Carlisle, coming across her, decided to change her into a vampire. After her transformation, she tortured and killed those who had beaten her, including Royce, but did not drink their blood.