An Apology for the Insensibility of Mr. Jones, to all the Charms of the Lovely Sophia; In Which Possibly We May, In a Considerable Degree, Lower His Character in the Estimation of Those Men of With and Gallantry, Who Approve the Heroes in Most of Our Modern Comedies
The narrator admits that some readers may be frustrated with Tom, since he doesn't immediately fall into Sophia's waiting arms.
Not only is she beautiful, but she's also really rich.
So why doesn't Tom just marry her, since she really wants him to?
The narrator explains that it's just Tom's nature.
Tom may not always think through the differences between Good and Evil.
But he does have basically good instincts, which lead him to do the decent thing over the sleazy thing most of the time.
He would never marry a girl just for her money.
And while he respects and admires Sophia Western, he is currently in love with someone else.
That girl is Molly, the second oldest daughter of Black George, the gamekeeper.
But Tom knows that, if he sleeps with her, her reputation will be ruined.
So Tom is doing his best to do right by Molly.
Molly, on the other hand, is much less worried about her virtue than Tom is.
She immediately does her best to seduce him.
But Molly does the seducing so subtly that Tom thinks the sex was all his idea.
Tom is totally convinced that Molly is in love with him.
And he wants to make sure that she is happy and well taken-care-of.
So it's because out of respect for Molly that Tom ignores Sophia's many charms.