Man, it's just a natural thing. If you both are pretending on a different parts of the same things - is it Ukraine (for Poland and Russia), Silesia (for Germany and Poland), Poland (for Germany and Russia), Europe (for America and Russia) you need some kind of mutual understanding and, better, a written (even if secret) agreement. If you don't have one, the risk of the things going terribly wrong becames too significant. So it is you who have a burden of proof that Germans and Poles have never discussed (even secretly) future of former Czechoslovakia, protection of human rights of ethnic Germans and Poles and territorial claims of each other.Evidence? Nazi documents seized after the war say you're just making stuff up.
Poor rewrite of history (unsupported by any evidence BTW). Hitler was determined to wage war, regardless of what any other country said or did (read Mein Kampf). No one trusted Stalin any more than they trusted Hitler.
Ok. For starters I'd recommend you to read any historical research, like, say, Herman Kahn "On thermonuclear war":
So, the clear determination of Britain, Czechoslovakia, France and Russia to fight the war (if necessary), demonstrated at May 19-22 of 1938 actually deterred Germany. And even if the war were started back in May 1938, the allies had had much better position to fight Germany and win the war with much lesser losses.