How is it possible that when bella slaps Paul in the new moon movie and nothing happens to her hand but in the eclipse book, when she punches Jacob her hand breaks?

That is a great question, and yeah, it probably was a little mix up in the script.
Unless she didn't hit him hard enough........?
;P

She "punches" Jacob with a closed fist..very easy to break bones...she "slaps" Paul with an open hand...very hard to break BONES（ボーンズ）-骨は語る- when the hand is open... :) Go Bella!

huh... I haven't thought about it... I really don't know, it's probably a mistake in the script または while directing... または it's just because they wanted to emphasise the punch-scene もっと見る than the slap-scene... it's a great 質問 though... you're very observant...!!!

omg wow that is a great freakin 質問 i would have never hought of it if あなた never 発言しました anything... yea that is pretty stupid.... i hope they have an explanation for this.... good eye ;)

well in eclipse she hits him in the chest and stomach area which i guess is harder then a cheek.
it's really confusing ,but that is my best guess.

Good point there.
But, yea, maybe she didn't hit him that hard.

well when she punched him she probably punched him with her thumb inside her hand and the force of the パンチ oushed back on her fingers so hard that it broke her hand. i know its confusing but yea.....i asked the same 質問 too.

Thats what i as saying too!
But i'm guessing that she Slapped Paul a little
bit, But full on Punched Jacob.

She probably didn't hit Paul as hard as she did Jacob