Complex sentence: The Allies were willing to risk exposing the double cross network, to achieve surprise for the Normandy invasion but early battle reports of insignia on Allied units, only confirmed the information the double agents had sent, increasing the Germans' trust in their network.
Split into simpler sentences: The Allies were willing to risk exposing the Double Cross network to achieve the needed surprise for the Normandy invasion. However, early battle reports of insignia on Allied units that the German armies encountered only confirmed the information the double agents had sent, increasing the Germans' trust in their network.