In Chapter 24 we see Fanny and William united for the first time, drawing some interesting commentary from the narrator on the nature and causes of happiness.
It was long before Fanny could recover from the agitating happiness of such an hour as was formed by the last thirty minutes of expectation, and the first of fruition; it was some time even before her happiness could be said to make her happy, before the disappointment inseparable from the alteration of person had vanished, and she could see in him the same William as before, and talk to him, as her heart had been yearning to do through many a past year. That time, however, did gradually come, forwarded by an affection on his side as warm as her own, and much less encumbered by refinement or self-distrust. (24.17)
Austen makes a really deep point that I doubt if any but a tiny minority would understand in our modern culture of distraction, that the agitation that comes with high expectations being fulfilled is actually stressful, and it is not clear that it should be labeled ‘happiness’. It is so-labeled because of our expectations, and this is the kind of excitement that we associate with romantic ‘love’.
Against this we have familial love.
An advantage this, a strengthener of love, in which even the conjugal tie is beneath the fraternal. Children of the same family, the same blood, with the same first associations and habits, have some means of enjoyment in their power, which no subsequent connexions can supply; and it must be by a long and unnatural estrangement, by a divorce which no subsequent connexion can justify, if such precious remains of the earliest attachments are ever entirely outlived. Too often, alas! it is so. Fraternal love, sometimes almost everything, is at others worse than nothing. But with William and Fanny Price it was still a sentiment in all its prime and freshness, wounded by no opposition of interest, cooled by no separate attachment, and feeling the influence of time and absence only in its increase. (24.18)
The point about familial love is that it is stable and long-lasting, and gives rise to real happiness (a point emphasised at the end of Sense and Sensibility). It is not that we shouldn’t have romantic love–the excitement of high expectation and so on is good for making things happen–but it must be transmuted into something more stable that will survive the inevitable trials. The true destination of conjugal love should be familial love. (See Howard Cutler in discussion with the Dalai Lama in The Art of Happiness, Chapters 5 and 6, for an excellent discussion of this point.)