Why would we trust Putin?
I can tell you why we don't: Communist or not, far too many people East of Greenland think wealth is acquired and not created. Therefore, other's wealth is their detriment. Simply stated, they believe in a zero-sum game. They may not believe in Communism, but they still hold the assumptions that made Communism seem attractive.
Belief in a zero-sum, finite wealth world could lead the to a US vs. Everyone war. Russia will not take our side.