Maybe we should go back? We don't want you dying of a cough.
True-true...
The cough's a mere nothing; it will not kill me. I shall not die of a cough.
Personification
Fortunato was dressed in carnival garb and wore "motley" with a conical cap and bells. He was dressed as a fool or clown. This is a symbolic representation of what he was.
Fortunato, who is suffering from a cold and is bothered by the nitre on the walls of the catacombs, tells Montresor that,"The cough's a mere nothing; it will not kill me. I shall not die of a cough." "True—true," I replied. Montresor already knows that's not how he's going to die.
When Montresor says, "My heart grew sick" It is an example of personification because your heart can't get sick.