"I promised myself that I would make him pay for this — that I would have revenge"
The character Montresor introduces his agenda and main idea of what the story's going to be about and the reader wonders what will happen next, when will the plot spring up again, and how will the characters resolve their problems.
In the beginning of the story, the only thing that we know about the main character is that he wants his revenge; no other details were provided to describe his personality in more depth. This uncertainty of the main suspect is an element of suspense.
Fortunato! How are you?
Montresor! Good evening, my friend.
As the reader witnesses the hero putting a lot of thinking and time into solving the problem that the reader doesn't know how it will be solved is another element of suspense.
I want to see your wine! Take me to your vault.
Throughout the story, the story foreshadows elements such as the wine and the bones of dead bodies and this is an example of an element of suspense.
Right this way
Are we near the wine yet?!
The author purposely states that the weather in the family vault is "cold and wet". It makes the reader get more nervous as to what's going to happen next and this is an element of suspense.
May he rest in peace!
As you can see, suspense is included in films and novels because it help makes the plot more exciting and enhances the difference between a good and great story.