Simply put, you have to convince them it was their own idea.

As for Germany and Japan, besides the fact they were well on the road to Westernization and modernization pre-War, the shock of their loss and utter devastation of their respective countries and economies, combined with the determination to recreate themselves, generously supported and protected by the United States with a national culture that enshrined perfectionism and a work ethic, it seems the effort was worthwhile.

This may be less effective in regions that has seen conquering armies transit to more welcoming climes, and the populace with infinite patience can wait out the invader.