Answer:
In "The Cask of Amontillado", Montresor is quite a proud a man who seems to have been utterly insulted. The story takes place around 1846 in Italy. We know that Fortunato has acted in a way that annoyed Montresor before, but there was something more specific, more insulting, that led Montresor to "bury" him alive. Taking the context and Montresor's personality into consideration, I would think Fortunato offended Montresor's masculinity somehow. Toward the end of the story, Fortunato mentions Lady Fortunato briefly. What if this Lady Fortunato, his wife, used to be Montresor's object of fancy? Maybe Fortunato acted swiftly and married the woman of Montresor's dreams! His name suggests fortune (wealth). Perhaps Fortunato happened to be more appealing, to offer a better life besides love and care for her. For a proud man such as Montresor, losing the woman he loved to a friend who has the habit of "injuring" him would be quite the insult.
Step-by-step explanation: