Montresor is capable of plastering Fortunato into a vault, but if he’s lying we still can't trust him because he isn't very trustworthy, reliable. It can influence the readers in many ways, for example they probably don't trust others as much as they did before.
The definition of personification is giving an object or an animal human characteristics. For example, the thunder grumbled like an old man. Another example, you can hear the wind whistling. Hope this helps
