Courage and truth are unrelated.
Hitler was a very courageous soldier in WWI. I am sure that he firmly believed in the motto "Gott Mit Uns". I am not sure of what the "truth" of WWI was. The Serbs blew up an Archduke (who probably deserved being blown up) and the Austrian-Hungarians declared war on the Serbs. So then the Russians had an alliance with their "little Slav brothers" and declared war on the Austrians, and the Germans had an alliance with the Austrians and declared war on the Russians, which brought France and England, as allies of the Russians into the war.
There should have been a better solution, like just giving the Austrians a notable Serb to shoot. But I do not think right and wrong or truth and lies has much to do with Hitler shooting at the Kaiser's enemy, or the Kaiser's enemy shooting back.
The point is that one can be brave and wrong, or cowardly and wrong, brave and right, cowardly and right. One does not become braver just because one's cause is just. Everyone who risks their lives pretty much believes that truth is on their side. The guys who ran the gas chambers at Dachau believed that they were improving the human race by gassing all those Jews, Mongoloids, cripples, Gypsies and leftists.