"Mr. Collins was not left long to the silent contemplation of his successful love; for Mrs. Bennet, having dawdled about in the vestibule to watch for the end of the conference, no sooner saw Elizabeth open the door and with quick step pass her towards the staircase, than she entered the breakfast-room, and congratulated both him and herself in warm terms on the happy prospect or their nearer connection. Mr. Collins received and returned these felicitations with equal pleasure, and then proceeded to relate the particulars of their interview, with the result of which he trusted he had every reason to be satisfied, since the refusal which his cousin had steadfastly given him would naturally flow from her bashful modesty and the genuine delicacy of her character."
Pride and Prejudice chapter 16

"By buying and selling luxury items and services with the explicit aim of enhancing pleasure and reducing pain, men and women pursued happiness in the manner that both Locke and Hobbes described- as a 'continual progress of the desire, from one object to another, the attaining of the former desire still but the way to the latter.'"
Happiness: a History page 206

In the first quote, Jane Austen gives an example of the language used in regard to happiness in the 18th century. This moment, taking place after Mr. Collins has explicitly described his plans to keep Elizabeth happy with his substantial income and inheritance, exemplifies the concept of happiness described in Happiness: a History. The couple has a "happy prospect"according to Mrs. Bennet, who throughout the entire novel is concerned with marrying her daughters to men of wealth. In accordance with the 18th century concepts of happiness, Mrs. Bennet believes that her daughters will live long happy lives as long as they have suitable funds to satisfy them. Collins also is depicted as having "equal pleasure" in the matter. These two characters have entirely disregarded the lack of emotional fondness between Elizabeth and Collins as a result of the belief that happiness is gained from material gain, a topic supported by popular opinion in the 18th century.