How is wealth of a foreign investor proven, validated, audited?

External question — Economics Stack Exchange Author: Nicholas Franceschina Original post: https://economics.stackexchange.com/questions/57278 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. Scenario: Crazy Rich Foreigner shows up in another country and wants to buy some very expensive goods/property. They purport to have massive wealth back home in their country's currency. They are also best friends with the king back home. How is that wealth verified/audited? How can we know they aren't just having their friend add some zeros to the end of their bank balance which they can then convert to dollars with regular exchange rate and buy up all the "stuff" in the other country? I'm new to this type of economic thinking... so I may not be asking the question correctly... happy to have any clarity!