I am new here and Rosalie is the one character I just can't figure out. Whereas the rest of the world seems to embrace Bella, Rosalie is hostile to her. We do see her warm up in Breaking Dawn, but as others have said that seems to be more about the baby than Bella herself.
Did I miss something?
, welcome to the Lex.
Everybody has their own interpretations of characters and events here, so there really is no one definitive answer. I can give you my opinion, though, so that's what I'll do.
For me, Rosalie embodies the "cautionary tale" of what it means to have your personality frozen in time as a vampire. They can adapt and learn throughout their lives, but the personality never changes except through very strong emotional events, such as bonding to a loved one. And, Rosalie does go through some changes when she bonds with her family, Emmett, and then Alice and Jasper. Still, Rosalie remains self-centered and vain, and retains all of her regrets from what she lost in her human life.
We don't get to see Rosalie in what would be her normal, typical, business as usual mode, because we only see her when Bella is around. Rosalie is jealous of Bella because Edward is attracted to Bella and not her, triggering her animosity due to her vanity. Bella is also human, which Rosalie is jealous of, and Edward wants to keep her human; the implication is that Edward loves Bella more than Rosalie loves Emmett since she made Carlisle turn him into a vampire. Perhaps most significantly, Bella wants to become a vampire and Rosalie does not respect her decision and cannot see why she would want to do this. Rosalie's regrets trumps Bella's wishes, and Rosalie simply cannot see Bella's point of view. Whatever issues Rosalie has, Bella triggers every single one of them, so Rosalie is always struggling not to show her contempt for Bella, and fails quite often. Rosalie is emotionally crippled, and she knows this, but there is nothing she can do about it. Read SM's extra from New Moon as a good illustration of this. Rosalie struggles to find sympathy for Bella, and knows she should be a better person, but ends up getting distracted by her reflection in the mirror.http://www.stepheniemeyer.com/pdf/nm_extras_miscalculation.pdf
It is implied that Bella's delivery of Renesmee and her near-death will change Rosalie's relationship with Bella, although even Bella still has her doubts. I suspect the relationship does change, eventually, but we don't get to see that.
So, keep in mind that since Bella is the narrator, we are always going to see Rosalie at her worst. I'm not going to try to defend her, but I do have a measure of pity for her since I see her in the role of that "cautionary tale" that I spoke of. Something also to keep in mind: Rosalie's often reprehensible behavior is triggered by the many regrets that she has for what she lost in life; think about how Bella would have turned out if she had gone ahead and aborted her child against her wishes and then had her personality and regrets frozen during her own change.