Why Does Montresor Keep Urging Fortunato To Go Back

First, Montresor pulls off some sleight of hand using reverse psychology in this
section. His ultimate goal, of course, is to lead Fortunato to his impending doom. In order to
further throw the man off any possibility of realizing Montresor's plans, he feigns concern for
Fortunato's health, urging him to turn back. But he also knows the man's pride, so any
insinuation that he is too weak to continue on the journey strengthens Fortunato's resolve to
continue.

Second, he weaves flattery into his efforts, further playing into
Fortunato's weaknesses:

Your health is precious. You are
rich, respected, admired, beloved; you are happy, as once I was. You are a man to be
missed.

Fortunato enjoys being admired, and Montresor
knows that if he flatters him while playing to his sense of pride, Montresor will actually
continue on the journey with him. It is also worth noting that Montresor uses verbalin noting
that Fortunato will "be missed," which Fortunato interprets to highlight his
own...