Montresor knows that Fortunato will be celebrating the "supreme madness of the carnival season," and that he will have been drinking heavily. Montresor also knows Fortunato's weakness: his love of spirits. Montresor concocts the story of the rare bottle of Amontillado (a Spanish sherry) knowing that Fortunato will not be able to resist the urge to sample it. Cleverly, Montresor also suggests that a mutual acquaintance, Luchesi, is available to give his opinion of the vintage if Fortunato is not able. Fortunato has no plans to allow someone else to spoil his chance, so he willingly follows Montresor deep into his catacombs, which also serve as a wine cellar. Despite the bones that are scattered throughout their path, Fortunato does not fear or mistrust Montresor: His thoughts are only on the Amontillado.
Montersor uses Fortunato's weakness against him. Fortunato believes he is an expert in wine thus he is blinded by pride. and Montresor uses that to triger his curiousity to taste that wine thus he teases him till he bury's him alive :D