...from a different book. This is from Jane Austen: The World of Her Novels. The first part of what she writes concerning the "short and intense flirtation" is nearly identical, including the "fright at the idea of an engagement between such a young and penniless couple". She goes on:

How deeply Jane's feelings may have been involved is not known; but even if she did shed some tears at hearing of Tom's sudden departure for London, only a few months later she started writing First Impressions, which is certainly not the product of a broken heart. Family tradition, however, recalled that she had been very upset when told by her parents of their impending departure from Steventon.