Mr. Nuttel is in two minds about his visit to Vera and her aunt. On the purely rational level, he recognizes the need to make social connections in a district where he knows no one and has only a tenuous link through acquaintances of his sister. Nevertheless, the problem that has driven him to seek rest in the country at the same time disinclines him from being very social:
Privately he doubted more than ever whether these formal visits on a succession of total strangers would do much toward helping the nerve cure which he was supposed to be undergoing.
As his sister has predicted, he is tending towards withdrawing from everyone else and "moping." He is not even tactful in his lack of enthusiasm for the visit that he is making at that moment:
“My sister was staying here, at the rectory, you know, some four years ago, and she gave me letters of introduction to some of the people here.”
He made the last statement in a tone of distinct regret. (my emphasis)
Mr. Nuttel thus sets himself up as a very understandable target for the imaginative talents of Vera. We can easily see that he is the sort of person she cannot possibly endure and will like to dispose of as quickly as possible, even if we have moral qualms about the way she will go about that disposal.