Nobody could stop Hilter. Only God stopped Hitler. The extreme and harsh Russian winter stopped Hitler. God created Hitler and assigned him the task of starting World War 2. When Hilter killed 80 million people God said "now it is enough. Now it is time for you (Hitler) to die".
Riiiight. This is what happened, over here in the real world: Napoleon conquered most of Europe, tried Russia, got beat, and fell as a result. The peace that was made after his fall was kind to France, and so France, not feeling the need for vengeance, settled back and mostly went about its business in the nineteenth century as a typical nineteenth century European major power. As stability gradually took hold, Europe gradually locked onto the classical gold standard, and the latter part of the nineteenth century wound up being unusually peaceful in Europe. During that peace, everyone built up their militaries. Then some fool killed an obscure Balkan prince, and all those militaries got used, and the 100 years of relative peace and stability Europe had enjoyed went up in smoke. But there was a difference this time: the US, which was a very minor power in Napoleon's time, had since become a major power, and stepped in on the side of the Western powers in WWI. That upset the whole European balance of power, and allowed France and Britain to exact a vengeful peace on Germany, rather than the kind peace that had been extended to France after Napoleon. The Germans built themselves back up, vowing to make the rest of the world pay for that peace. Allied with a newly modern Japan, they came very close to actually succeeding, except that in the intervening decades the US had become even more powerful, and used its endlessly productive economy to turn out enough planes and tanks and boats and bombs and bullets and trucks and jeeps to bury both the Japanese and the Germans. Under US supervision, the peace that ensued was kind instead of vengeful, and so the world has enjoyed, since then, 65 years and counting of relative peace and stability. No one ever really wants to acknowledge this simple truth, but from the Barbary Pirates to the Nazis and the Communists, the US has been on the side of peace, order, and international good behavior, simply because at its core, the only real thing the US is concerned about is commerce. That seems crass to a lot of the rest of the world, but commerce is all about making deals that profit everyone, and that's a lot better than pursuing wars that only destroy everyone and everything involved.
Hitler had survived 42 assasination/killing attempts before World War 2. Hitler used to say "God is helping me".