https://www.stormfront.org/forum/t1863/I have been looking for the exact source of this quote for decades--not metaphorical decades, but actual decades. It has eluded me.
However, David Irving gives the following in the last chapter of his masterwork, Hitler's War:
[Hitler] dictated to Ribbentrop four secret negotiation points to put to the British if he got the chance, points vital to the future of Europe. If the Continent was to survive in a world dominated by bolshevism, then somehow London and Berlin must bury the hatchet between them. He instructed Ribbentrop to write secretly to Churchill in this sense.
"You will see," Hitler predicted. "My spirit will rise from the grave. One day the world will see that I was right." (Vol. II, "Eclipse," pp. 886-887)
Irving gives the source for this in Ribbentrop's documents.
He also quotes Hitler similarly as saying:
"It shall not be! These illiterate brutes shall not inundate all Europe!...I am the last bulwark against this peril. If there is any justice, then we shall emerge victorious. One day the world will see the moral of this struggle. (Vol. II, "Hitler Goes to Ground," p.857)
So the unverified quote attributed to Hitler is indeed in Hitler's characteristic mode of thought and language--but it is still unconfirmed. However, just because the source for the quote is presently unknown does not necessarily mean that it is a fake.