Breaking Dawn concludes Bella's story. But not before putting her through the ringer of marriage, sex, pregnancy, motherhood, and rebirth as a vampire – in that order.
After Bella and Edward celebrate a fairytale wedding, surrounded by their loved ones – including vampires, werewolves, and humans – they head off to their honeymoon on Isle Esme. Although Bella looks forward to Edward fulfilling his side of the bargain, which is to make love to her, she's nervous. After all, Edward is her first boyfriend, so she doesn't quite know what to expect.
But the morning after they've made love for the first time, she wakes up, reveling in complete bliss. Even after she discovers the bruises Edward inflicted on her in the heat of the moment, she maintains that she can't imagine that human life gets any better than making love with her new husband. In fact, she decides to stay human for longer for the sole chance of repeating the experience. And when Edward resists, she has no qualms of resorting to her female weapons to tempt him: "I started out slow with innocent ivory satins… ready to try anything" (6.8). When she eventually gets her way, she still can't get enough. In fact, were it not for her need to sleep and eat so much all of a sudden, she'd probably never give Edward a rest.
And what's up with the violent dreams about her attempt to save the vampire baby…? At this point, you'd think that anyone involved in a sexual relationship would connect the dots between "sex" and "no protection" and "children," but not Bella.
However, once Bella does put the evidence together (which is easy math, what with the growing stomach and acute nausea), she handles the discovery far better than Edward does. Even though she has no clue what exactly is growing inside of her, she almost immediately falls in love with it and naturally adopts the role of a mother who sees her sole purpose in protecting her child.
Bella's decision to sacrifice her life for that of her child has sparked much controversy among fans and critics alike, who question whether Stephenie Meyer is making a pro-life statement in Bella's radical choice. Here's what Meyer had to say:
…the only thing I can answer to that is that I have three children and I know what I felt like with each one of those children and if someone had told me "if you carry this child to term, you will die," I would have done it anyway. That's how I am. My experience as a mother is reflected in that part of the story. (source)
Throughout the whole sex and birthing drama, surprise or no surprise, Bella follows her heart with a dogged sense of determination and a trust that things will just work out fine. And they do. After she endures the pains of childbirth, closely followed by the atrocious pain of transformation, she pops out the other end as a beautiful, graceful, strong vampire.
Unlike other newborn vampires, Bella's willpower and self-control allow her to manage her thirst for blood. As Meyer explains,
If you think about all the other vampires that have been created… none of them had a lot of time to think about this or were even asked, they were on their death beds and they awakened a vampire with no preparation at all. Then you have vampires like the Volturi, who become vampires and immediately expect to prey on humans because that's what vampires do. Bella's kind of unique in that she had a couple of years to think about what she wanted to be and she was going to do that. So she had way more preparation than anybody. And she was already a stubborn girl. (source)
After the Cullen family and Jacob become convinced that Bella doesn't pose a threat to Renesmee, she immediately takes on her role as a mother. She even endures a visit by Charlie without attacking him, although she experiences his delicious scent as "a fistful of flames, punching straight down [her] throat" (25.208).
Happiness becomes the main component in Bella's life. The ease with which she slips into her new vampire self seems to suggest what many characters, including herself, come to believe: it was Bella's destiny to be a vampire:
As a human, I'd never been best at anything… After eighteen years of mediocrity, I was pretty used to being average… I just did the best with what I had, never quite fitting into my world… It was like I'd been born to be a vampire. (26.130-131)
You'd think that being a beautiful, strong vampire mother, surrounded by a family of humans, vampires, and werewolves, would be about all the wonder Bella could handle. But it gets even better. The quirk of her private mind, which has long blocked any vampire, no matter how gifted, from reading her thoughts, turns out to be a powerful, dormant shield. Surprise or no surprise?
Here's how Stephenie Meyer came up with the idea for Bella's shield:
It was already part of Bella's character. She had this hidden strength and it was always about her strength of mind, mentally tough. (source)
Bella's shield allows her to protect the ones she loves and to ultimately prevent a war with the Volturi. She becomes a true heroine, saving the day for everyone. In the end, she even manages to push her own shield out of her mind so that Edward can read her mind for the first time ever and see how much she truly loves him. So her story concludes "in this small, but perfect piece of forever."
For more info on Bella and to catch her entire story, check out the other books of the Twilight series on Shmoop.