The final sentence is your post is most telling. It reminds me of a sentence from the book “Backlash”.
It goes like this: “Roosevelt cloaked his guile with a personal charm reputed to be so overpowering that some political foes were said to shrink from private encounters with him lest they succumb to his wiles”.
In that, Stalin was one of the few who was not swayed by Roosevelt’s persona.
Yes, that was a big part of the problem with Yalta, etc. Roosevelt was so accustomed to charming or overpowering almost anyone in his orbit with his personality that he could not grasp that Stalin was quite immune to such personal appeals and would go on acting purely from a combination of self-interest and national interest of the USSR as determined by Stalin. Of course, it is debatable whether the US really had any good cards to play w.r.t. the future of Eastern Europe, since with Soviet troops occupying THEY were going to call all the shots whether we liked it or not. We might have gotten them to make a few more promises, which would probably have been broken just as easily as Stalin snapping his fingers and jailing or executing anyone who got in his way. Nothing short of General George Patton’s WWIII was likely to force the Soviets out of Eastern Europe, but we might have been much better prepared and somewhat more effective in trying to influence some specific events if Roosevent and then Truman (in the latter’s first months in office, he did start to wise up later) had not been so gullible and naive.