Betrayal drives the action in “The Cask of Amontillado." One character’s betrayal sets off a hideous chain of retribution, enacted below ground in a mass grave. Behind all this revenge and death, the story is about trust. Without trust there can be no betrayal. The story has much to do with the lengths human being will go to feel better when they feel betrayed – and the tragedy that comes when those lengths hit murderous extremes.
Fortunato betrays himself by not paying enough attention to his surroundings.