The thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult I vowed revenge.
My dear Fortunato, you are luckily met. How remarkably well you are looking to-day, but I received a pipe of what passes for amontillado and I have my doubts.
--ugh! ugh! ugh! It is nothing
How long have you had that cough?
Come, we will go back; your health is precious.
From the beginnig of the story, Montresur is already in plan to murder Fortunato. He wants to take revenge but without being caught.
Besides, there is Luchresi...
Montresor feels delighted to see his 'friend' Fortunato. However, we know he only wants revenge towards Fortunato, so he uses his hypocrisy to fool Fortunato.
Montresur falsely pretends he is preocupied for Fortunato's health. When in fact all he wants is to get rid of Fortunato
Montresor knows how proud Fortunato is, so he uses this to his advantage to get Fortunato to go with him to find the amontillado. Without even knowing Fortunato is leading and insisting his own death.
The cough is a mere nothing.
For a brief moment Montresor was hesitant and was even trembling, but his satisfaction on burring Fortunato alive instantly came back to him. He even shouted louder to let know Fortunato know that no one would hear him.
For the love of God, Montresor!
Yes, for the love of God!!
Montresor called Fortunato but there was no response. So here Montresor got his revenge and killed Fortunato. Getting away with it and nobody finding out for over 50 years Montresor got what he wanted.