Incomplete question. However, I infer you are referring to the story "The Censors".
Answer:
Likely because of his background.
Explanation:
More likely his background affected his concern for Mariana. Probably be had experienced government censorship of information where he lived, and so thought it was in such neighborhood that Mariana lived.
However, Mariana was in a hidden Paris neighbourhood likely different from Juan's own.
The first one has alliteration in the beginning, but not in the end. The 2nd sentence is barely alliteration, the 3rd one has no alliteration, and teh 4th sentence repeates the -eed sound.
He was swayed by both these considerations: the marriage gave him personal satisfaction, and at the same time it was considered the right thing by the most highly placed of his associates.
