Do you think the vampire transformation would be more painful to Bella than being left by Edward? Or is it just a different kind of pain? I need to know this.

Vampire transformation is physically painful-beyond-imagining, but it is temporary. Bella knows the end is in sight. She is able to control herself and hold herself absolutely still & silent while she is enduring it. Like Edward says, "Mind over matter." Even when she thinks the pain of it might kill her, she is still and silent. This pain has always been, for her, worth risking everything.

Being left by Edward is emotional pain that manifests itself in physical ways: night terrors, sobbing, numbness, and physical pain to the point where Bella feels as if she has to wrap her arms around her body to prevent it from falling apart. This pain is unknown; Bella doesn't know when it will end, if at all. This pain is one that she has to carry with her day and night; she can't give over to the misery, but has to go on. Mind over matter won't let her escape this pain because the pain is emotional at its source.

What if your glittery soul mate left you for no reason and disappeared without even a trace? Ouch.

What if he bit you so you could be with him f-o-r-e-v-e-r? Bring the pain! I can take it!