What does Fortunato believe is actually happening in "The Cask of Amontillado"?

Fortunato prides himself on being a
connoisseur of wines. He also believes that he is still good friends with Montresor. Montresor
lets readers know from the beginning of the story that their friendship is tenuous at best and
that he is planning on getting revenge against Fortunato. Montresor seeks out Fortunato during
the carnival celebration and lets it be known that he has miraculously obtained a full pipe of
Amontillado sherry. Montresor states that he isn't convinced it is real, and Fortunato excitedly
volunteers his palate and tells Montresor to lead the way to the wine vaults.

Come, let us go.

Whither?

To your vaults.

This is all part of
Montresor's plan, so he begins taking Fortunato to his home. Fortunato believes that he is going
to get to taste an amazing wine when, in reality, he is being led to his
death.