Europe 1936-39: the slide to war
Hitler's actions between 1936 and 1939 did lead to war in Europe. That is not the same thing as saying that Hitler wanted a war in 1939 or that it could not be avoided. Neither does it mean that Hitler was the only cause of the war. It is quite possible that Hitler did not expect to have to fight a war with Britain and France over Poland. He was probably convinced he could seize Poland without involving other European powers.
The Rhineland: the turning point
In March 1936 Hitler ordered German troops into the Rhineland area of Germany. According to the Treaty of Versailles, no troops or military defences were allowed in the Rhineland. France was ready to take a stand over this breach of the treaty and sent troops to the border with Germany. France was prepared to force Hitler to back down if Britain agreed to support her. Britain made it clear that she was not prepared to go to war to keep German troops out of their own territory (the Rhineland). Britain was desperate to avoid war with Germany and, like France, overestimated the size of the German armed forces. France was sure that the German army numbered 295,000 men and that she could not fight them alone. In fact, the German army was nowhere near as powerful as this at this time.
For Hitler, the gamble paid off. The French backed away and Hitler's secret orders to his men to withdraw from the Rhineland, if they were attacked, were never needed. Hitler was convinced that he could achieve what he wanted without a war because Britain and France would never stand up to him.
Neil Demarco: The era of the Second World War; Oxford University Press, 1993/2000, page 17