If it's the discussion in the railway carriage in Finland, then "realistic and reasonable" is not entirely accurate. He's telling Mannerheim a pack of lies. Remember, his Foreign Minister signed the M-R Pact with it's secret protocol giving the Soviets a green light to invade Finland in 1939. Then in 1941 he negotiated with Finland to join Barbarossa to retake the lands lost in the Winter War.
Giving his excuse to Mannerheim about why he didn't send troops to aid Finland in the Winter War, he claims his generals wouldn't let him invade France in October 1939, so they had to wait until May 1940 (when the Winter War was all over), because his army was not equipped to fight in the (French) winter. This is the only claim I've ever heard that Germany could have redeployed all of it's troops to France immediately after the Poland invasion. And Hitler was never one for listening to his generals. Borne out by the fact that only a few months before he had ordered those generals to fight the Battle of Moscow in the (Soviet) winter (far worse weather than you would ever get in France) and lost. And only a few months after this meeting he ordered his generals to fight the Battle of Stalingrad in the (Soviet) winter.
Yes, it's slightly surprising to hear someone talking calmly, given the way he conducted himself in his speeches. But there was never any suggestion that at Munich or other meetings with world leaders, or even meetings with his own party members that he was always a ranting lunatic, in the early years at least. He was more often described as boring, given interminably long diatribes about things. What matters is not how he spoke in private, but what he did. And by the time of this recording he had signed the order which forever marks him as one of the most evil men in history.
