Student or Learner
I read this from The Decline and Fall of Practically Everybody by Will Cuppy:
"He said he hadn't an inkling until the crown was actually placed on his head while he wasn't looking. He felt something tickling his brow, and darned if it wasn’t the imperial crown."
What does "darn" mean in this context?
"Well! I'll be damned!", someone might say when completely suprised.
Damn becomes darn. Pure euphemism.
"I'll be darned if that's not true" means "I'm surprised, but I'm now sure that it's true."
"Darned if... NOT...", going from the exclamation, therefore at its strongest would mean something like "and he was suprised to see that..."
But in fact the idiom has become much weaker: "and darned if it wasn’t the imperial crown" just means "and behold! it was the imperial crown."