"That girl has become a beautiful woman."
Translation:Quella ragazza è diventata una bella donna.
What's the difference between "è diventata" and "hai diventata"? Is "hai diventata" wrong?
what is the difference between diventare and divenire (diventato/ divenuto respectively)?
"Diventare" is more common, you can always use it.
"Divenire" is used less often. I wouldn't learn the cases where you can or can't use it, and would rather stick to "diventare"
Something on the topic here... http://forum.wordreference.com/showthread.php?t=549789
When the adjective comes before the noun (i.e., "bella donna"), it's usually seen as more emphatic. When saying "She has become a beautiful woman," it feels more natural, but both are correct.