What does Montresor admit is his motive for committing a crime in "The Cask of Amontillado"by Edgar Allan Poe?
Montresor never admits to a clear motive for killing Fortunato, speaking only in the vaguest terms about it. First, he says he has suffered a "thousand injuries" from Fortunato. We have to assume this is hyperbole, which is figurative language based on exaggeration. Since we know that Montresor is telling the story many decades after the fact, he must have been a young man when he murdered Fortunato. How could there have possibly been a "thousand" injuries? The fact that Montresor exaggerates suggests to us that he has an inflated or unrealistic idea of how he has been wronged.
However, Montresor brushes off the thousand injuries and states that, in fact, it is being insulted that determines him to pursue the path of revenge. An injury is actual damage or harm that a person endures. An insult is being spoken to or treated with disrespect. We can conclude from this that Montresor is a very proud person, who has little toleration for being disrespected. We know, too, that later on, Fortunato will speak with disbelief at the idea that Montresor might be a mason, thinking Montresor means he is a member of the freemasons. Fortunato says:
“You? Impossible! A mason?”
Montresor, however, means he is a literal mason who will wall Fortunato up to die.
It could be that Fortunato is simply a high-handed person who thinks he is better than Montresor, and Montresor, being mentally unstable, can't tolerate that. It could also be that he is walling up Fortunato due to some insult having to do with freemasonry.
The important point is that whatever Fortunato has done or whatever Montresor perceives him to have done, walling him up to endure a slow, horrible death in the catacombs can't possibly be commensurate with whatever "crime" he committed.
Montresor is the protagonist and narrator of "The Cask of Amontillado" by Edgar Allan Poe, and he claims from the beginning that the reason he had to seek revenge is that he was insulted. We do not know until the story unfolds exactly what that means, but he expresses his motive clearly in the first line of the story:
The thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult, I vowed revenge.
Here is the problem: Montresor is not a reliable narrator. What he says may have some truth in it, but we cannot trust his judgment. If the insult were serious enough to warrant being murdered, a "sane" person would not have been able to act as if nothing were wrong until he had the opportunity to arrange a murder.
It must be understood that neither by word nor deed had I given Fortunato cause to doubt my good will. I continued as was my wont, to smile in his face, and he did not perceive that my smile NOW was at the thought of his immolation.
If the insult were serious enough, the one who gave the insult (Fortunato) would not have been on such friendly terms with the man he insulted so strongly (Montresor).
While it is clear that Montresor is perfectly capable of planning and executing a well-staged murder, he is not rational about his reason for doing so. He accepted "a thousand injuries" before this one insult, and yet the one insult was enough to prompt a murder. That is not rational thinking.