Think about whether or not Montresor is an unreliable narrator in "The Cask of Amontillado." Think about whether or not Montresor is an unreliable...

Montresor is an unreliable narrator, yes, because he is clearly mentally unstable.  He cannot be trusted.  In addition, there is no evidence that Forunato did, in fact, insult or do anything of great harm to Montresor at all in the story.  Poe provides no details.  Because the narrator is unreliable, we cannot trust him when he says that Fortunato has wronged him.  We do not know if this is true at all.  EVen if Montresor HAD provided evidence, we still could not trust him because he is an unreliable narrator.  For all we know, he could be making it up.  It does not take long to look for evidence to support the fact that Montresor cannot be trusted and is unreliable because of his murderous plot and because he is emotionless and remorseless for what he is doing.  He has no regrets and is happy with his plans.