Yeah, I understand it's human nature to want what you can't have, but Rose seems a bit too selfish for me in her speech. Also, they can actually be part of all those things, maybe just a tad less time than a normal people can, but they still can be so. It's not their vampiric nature that prevents it, it's the Vulturi's laws that do. So being a vampire is not what's there to blame... I dunno, Rose is too dramaric at times..
Rosalie is definitely on the dramatic side, and I would say Edward, pre-Bella, was right there with her. I sort of think they were/are the type of people who identify so strongly with their disappointment/unhappiness that giving that up is almost worse than actually being disappointed/unhappy? Edward’s entire worldview was “I am a horrible monster who deserves nothing good” and then even when Bella shows up and good things happen he can only see it through a bad things lens. Instead of “she wants to be with me forever” it’s “she’s going to lose her soooooul because of meeeee.” Rosalie has staked this ground of being pissed off that she was denied the very simple things she wanted–namely children–and it’s become a major part of her perspective. She can’t see Bella becoming a vampire as a good thing because to her it’s giving up all the things she personally wants.
In Rose’s defense, though, Bella’s the same way. She can’t see how becoming a vampire might be a bad thing, can’t understand Rosalie and Esme’s sorrow at not being able to have children. So it works both ways. I keep thinking about Bella in New Moon and her depression, and how she says something like “it wasn’t just losing the truest of true loves, it was losing the whole future, the whole family I’d chosen.” Rosalie probably feels the same way. The future she chose was a human one with children and she lost that. And unlike Bella, she hasn’t gotten it back in then end. She got “half.”
Rosalie does have a selfish streak, though, there’s no denying that. One thing I love about her is that she owns her faults and admits that she can be self-absorbed. She doesn’t see herself as a saint, she knows she has flaws. It’s easy to get frustrated with her and be like “but look at all the good things you DO have! Don’t dwell on what you’ve lost, appreciate what you have!” but people in general don’t work that way and Rosalie Hale specifically I think doesn’t work that way. Hopefully she will find peace and happiness–and Renesmee might be a part of that, at least for the time being–but I think it’s always going to be an uphill battle for someone with Rosalie’s personality.