It's not hard to believe that no one knew that Clark Kent and Superman were the same person. Clark was clumsy and unsure. He was nervous and scared. Superman was strong and sure and always had everything under control. What I don't understand is how Lois Lane never saw it, never knew all of the amazing things that Clark could do. It seems impossible to me, because I can see it in him.
Each time he knocks something over, or trips on his own two feet I can see him leaping tall buildings in a single bound. Every time he burns his hand on a coffee pot I know it's his heat vision just a little off target. I know that he wears those goofy glasses just to keep his super human vision in check. I like to believe that that scar just above his knee is just there for show because the image of a bullet ripping through it is just too impossible.
Maybe Lois couldn't see it because it wasn't there. Maybe they got it wrong, and Superman and Clark Kent were just two entirely different people. Maybe one is just a myth. It wouldn't surprise me. After all I see Superman every day but I've never met Clark Kent.