Welcome to the forum , newtothis .
As others have mentioned , ownership of 'International Art' that may have been stolen is a bit of a slippery slope .
This does not mean that yours is actually a stolen work , or from where you think (or were told) it came from .
I did a bit of covert checking on yours , and have not found it on any national or international "hot sheets' or 'watch lists' .
I regularly check on such things when buying paintings , so I've got a bit of a clue about doing so .
I'll comment that often 'sellers; will "invent" stories about paintings to facilitate their sale , usually kind of a rush-job .
Some buyers (collectors especially) don't give a hoot where or how a painting was acquired , and con-men have used this angle for selling both real & fake items for centuries .
Statutes of limitations apply in many cases , with so called "International" art ; there's also problems with loss of (or lack of) ownership paperwork (wars , fires , floods , thefts etc.) from the original owners .
Possesion is still pretty much 9/10's of the law when no paper trail exists , generally , sorta-kinda .
As others mentioned , it would be nice to see a good quality image posted here , of the artists' signature .
I'd like to see an image of the 'republic of hungary' stamp you've mentioned too .
Perhaps members here can help with your researching .