I always hope the world will be peace! 
I am afraid there won't be peace as long a humans exists. That is the human nature - we fight. There will be always wars as long as there will something worth fighting for.
I think the human nature argument is overrated. In extreme cases, yes humans are violent, as any other animal is. But if people have their basics covered, I don't see why this is true. I think at that point it's more of a cultural thing: we accept the idea of attacking others for our benefit. Fortunately, cultures change.