In 1933 when Hitler heard of SA terrorism in Silesia, Danzig and East Prussia, he began to distance himself from such actions and wanted to reassure the Poles that he wanted friendship with them and hoped for some sort of treaty between Germany and Poland:
Hitler began to extricate himself from this situation during a conversation with the Polish ambassador Wysocki on 2 May 1933: the frontiers with Poland were a bone of contention dropped between Poland and Germany by the allies, he respected Poland as a reality and hoped that their respective interests could be discussed dispassionately. The speech of 17 May, in which Hitler averred that 'we respect the national rights of other lands too and would, from the bottom of our hearts, to live with them in peace and freedom' was also aimed at a Polish audience. A similarly reassuring tone was kept up after the German departure from the League of Nations on 19 October 1933 reawakened Polish fears and Polish plans for a preemptive war. On 24 October he tried to reassure the Poles with his speech 'There are Germans in Europe, there are Poles in Europe', while in November he stressed a community of interests in combating Soviet communism:
"The Chancellor declared that acts of aggression contradict his policy and that a war would be a catastrophe for everyone. Any war could only bring communism to Europe which would be a terrible danger. However Poland is an outpost against Asia. The Chancellor took up the thought that every possibility of war must be excluded from German-Polish relations whereby he remarked, that these thoughts could be given the form of a treaty."
Michael Burleigh,
Germany Turns Eastwards A Study of Ostforschung in the Third Reich, page 65.
A year after signing the non-aggression pact with Poland, Hitler said on 21 May 1935:
Germany has concluded a non-aggression treaty with Poland with no consideration for the past, as another more than useful contribution to the European peace that not only will hold blindly but from which we only have the one wish: It will be renewed again at every expiry of the set period, and the friendly deepening of our relations resulting from it. [...] With the understanding and the warm friendship of sincere nationalists, we recognize the Polish State as the home of a large patriotic people.
At that time, Hitler didn't pose a threat to the Poles.
Yet, in 1939 his mood changed after his successful annexations of the Sudetenland, Austria and he said in May 1939:
With minor exceptions German national unification has been achieved. Further successes cannot be achieved without bloodshed. Poland will always be on the side of our adversaries... Danzig is not the objective. It is a matter of expanding our living space in the east, of making our food supply secure, and solving the problem of the Baltic states. To provide sufficient food you must have sparsely settled areas. There is therefore no question of sparing Poland, and the decision remains to attack Poland at the first opportunity. We cannot expect a repetition of Czechoslovakia. There will be fighting.
On 22 August 1939 he was even more clear when he spoke to his military commanders and said:
The object of the war is … physically to destroy the enemy. That is why I have prepared, for the moment only in the East, my 'Death's Head' formations with orders to kill without pity or mercy all men, women, and children of Polish descent or language. Only in this way can we obtain the living space we need.
There is absolutely no way that the Poles had any place in the Third Reich and what is absolutely certain is that both Poland and the Poles got in the way of Hitler's Lebensraum ideas for Eastern Europe.
Even as early as 1937 the Nazis were keeping a close eye on the Poles living in the Reich:
Preparatory work included monitoring the activities of the 1,200,000 Poles living in Germany, including a card index of 'frontier-political untrustworthy' Poles and Germans; a campaign to 'germanise' Police place, street and family names in the eastern regions and, as we have seen, efforts to foster German national consciousness at the expense of Sorbian ethnicity in Lusatia.
Michael Burleigh,
Germany Turns Eastwards A Study of Ostforschung in the Third Reich, pages 146-147.