The Germans believed that Great Britain would decide to stay out of the war.
Explanation:
Schlieffen in his plans had made plans to take France by surprise and that a big and successful attack against France was going to be enough to stop Britain from being involved in the war. And This would give the Germans time (Schlieffen had built his plans around six weeks) to move soldiers who had been fighting the French to Russia to take on the Russians.
The attack on France was to be done through Belgium and Luxemburg. Britain in 1839 had guaranteed Belgium her neutrality. Schlieffen's strategy for success was dependent on Britain not supporting Belgium.
