She didn't die, she was slightly poisoned.Please, sakura almost died when a tiny bit of Kurama's chakra seeped into her arm.
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And she managed to heal NAruto right afterwards from dieing, as i recall.
It said it in the manga, read the OPLol
The taming of Biju's got nothing to do with willpower - it's literally fighting a 50% Kurama one-on-one, surviving and managing to stun him for long enough to take his chakra. Are you saying Sakura can solo Kurama? Yeah, nope.
Sakura can grow super big,
and yes she can.