] two gentlemen pronounced her to be a pretty girl. Such words had their due effect; she immediately thought the evening pleasanter than she had found it before

That part goes on to say:

--her humble vanity was contented--she felt more obliged to the two young men for this simple praise than a true quality heorine would have been for fifteen sonnets in celebration of her charms

Well, you guessed it! The 'true quality heroine' Emily St. Aubert in Udolopho does have a secret admirer composing sonnets to her in the first chapter of the book! He writes it on the wall of a little cabin the family has (where they can go to admire scenery). An exerpt:

The sweet expression of her pensive face,
The lignt'ning smile, the animated grace--

(snip)

And who that gazes on that angel-smile,
Would fear its charm, or think it could beguile!