The Twilight series had many interesting and loveable characters, but all of them aren't without their flaws. The Volturi became more possessive, and Jacob crossed boundaries, and even the Cullens weren't invincible to the effects of time on their character.
Rosalie Hale was introduced in the first book as one of the Cullen siblings. Although the series focused on the relationship between Bella and Edward, and the intrusion of Jacob as he tried to leave the friend zone, Rosalie made an impression on the audience, and not always for the right reasons.
She Is Portrayed As Simply The Beauty & Nothing More
Rosalie is beautiful. She was beautiful before she became a vampire, and even more so after her transformation. It is made clear in the series that she makes people uncomfortable because of her looks.
But she wasn't only beautiful, she was smart, a musician, and loved to dabble in mechanics, which is mentioned in the first book. Most of this is forgotten and she becomes worse because of it, becoming mainly known for her beauty.
Her Playful & Loving Characteristics Are Sidelined
Rosalie is mainly shown as being self-centered, loyal, and serious. But she is playful around Emmett, which is hardly shown except for her comment of "monkey man," during the baseball game, and some scenes of affection.
She plays piano at Edward and Bella's wedding, which isn't included in the films, and her affections toward Renesmee give the impression that she never cared for Bella, giving her motherly attributes a shallow taint.
She Lets Her Vanity Control Her
Rosalie was meant to be paired with Edward. At least, that was Carlisle's hope after the found her dying on the street and turned her into a vampire without her permission. But the two of them never clicked, neither being interested in the other.
Rosalie, however, thought that Edward's lack of interest in her was insulting despite disliking him. When Edward fell in love with Bella, Rosalie's vanity blinded her relationship with Edward, letting his rejection get in the way of their friendship, while her interactions with Bella barely even existed.
She Continues To Doubt Edward
When the Cullens learned of Bella's possible future as a vampire, they trusted Edward to do what was right. "Cullens," meaning Carlisle, Esme, and Alice. Emmett was wary at first, but eventually came around and welcomed her into their lives. It was Rosalie and Jasper who remained unconvinced.
In fact, they had planned to kill Bella after Edward saved her from Tyler's runaway truck. It was only because of Carlisle's intervention that Rosalie changed her mind. She continues to doubt Edward's choices throughout the entire series.
She Forces Her Values On Others
Bella wants to spend eternity with Edward, but she also wants to become a vampire because she believes that she was always born to be one.
She never felt like she belonged as a human. She had a natural immunity to vampire talents. She was clumsy and always out of place. But Rosalie doesn't care. She's offended by Bella's lack of respect for mortality and tries to enforce her beliefs on Bella.
Her Sibling Relationships Hardly Exist
In the films, not much focus is given on the Cullen sibling relationships if they don't include Edward in the mix. A skeleton is given for viewers as they attempt to find something meaty onscreen when it comes to Alice and Jasper, Rosalie and Emmett, and Carlisle and Esme.
Rosalie is always shown to be by Emmett's side, and vice versa. This makes Rosalie seem more closed off and standoffish. But in the books, Alice and Rosalie are quite close, and Rosalie expresses her love for Carlisle and Esme.
Her "Mean" Character Overshadows Her Reasoning
So much focus was given to how much Rosalie disliked Bella that Rosalie was a semi villain, the only member of the Cullen family who didn't want her to join them while all the others agreed to her transformation.
They gave her a gut-wrenching backstory, and she was still disliked because by the time her reasons for disliking Bella were revealed, the audience already had an opinion toward her character. Only, they added sympathy to the list. Rosalie isn't looking for sympathy, she's a strong female character given a bad rap.
Her Self-Pity Is More Than Her Appreciation
Rosalie pities herself and thinks too much about what could have been instead of focusing on what she has and what she can become. She didn't want to be a vampire and continues to despise her existence after all she gained from it.
She adores her supreme beauty and found the love of her life, Emmett, by saving his life. Carlisle gave her a second chance at life despite his selfish intentions at the time, and she has a family who loves her.
She Liked Bella Because Of Renesmee
Rosalie never wanted to become a vampire, and it wasn't a fate she would have chosen for Bella. She always wanted a family, to be married and have children. When Alice saw Edward and Bella's future resulting in either Bella's death or transformation into a vampire, Rosalie was furious. She voted no to Bella becoming a vampire, saying she wished someone was there to vote no for her.
Although Rosalie does warm up to Bella, the main reason is because of Bella's baby. She becomes possessive over Renesmee and puts her own desire for a family ahead of Edward's consultation on the threat to Bella's life.
She Puts Her Own Feelings Above Edward's & Tells Him Bella Is Dead
Rosalie is the one who tells Edward that Bella is dead. She did it despite her family telling her not to. She doesn't do it with kindness or remorse, but in a heartless and casual way.
She wanted Edward to get over it so things could go back to normal, putting her own feelings above his. She tells him to grow up and think of something other than himself, treating Edward's affections and moral crisis as though he enjoyed suffering and the drama of it all.