Marianne has to be dramatic. She strikes a pose and tells Elinor she has been unjust: ‘I have been open and sincere where I ought to have been reserved, spiritless, dull and deceitful.’ She goes on with typical adolescent histrionics to say it would have been well enough if she had only spoken of roads and the weather and that only once in ten minutes. The less sensible Mrs. Dashwood chooses to see Elinor's half-reproof as a jest. She herself is pleased with Marianne's delight in conversation with their new friend.
At one point in the novel, Marianne sees Edward approaching and mistakes him for Willoughby; later she similarly mistakes Colonel Brandon for Willoughby. It seems strange for a woman so in love that she is unable to pick out the body style, horse, or clothes of her man even in a small crowd! No doubt, Jane Austen wants us to see that Marianne’s judgement is so clouded by her romantic outlook that she ‘fills in the blanks’ of Willoughby’s character, by culling from novels and daydreams her notions of the perfect man. It is ironic that she mistakes the truly good men for Willoughby. Perhaps they look very manly at a little distance.
Marianne and her mother have similar characters. Mrs. Dashwood is passionate and imprudent. She says: ‘I have never known what it is to separate esteem from love’. Of Marianne, Jane Austen writes: ‘She was generous, amiable, interesting: she was everything but prudent. The resemblance between her and her mother was strikingly great.’
Marianne's sensibility is not confined to the pangs of love. Like her literary heroines she cultivates an exquisite taste for poetry, music and the picturesque (as defined by Gilpin, the New Forest vicar, whose writings on the picturesque also influenced Henry Tilney's tastes). This was the time when water-colours had become a craze. Artistic tourists attempted on-the-spot watercolours to record what they saw, just as the modern tourist uses a camera. The Society of Painters in Water Colours was formed. Jane Austen enjoyed the picturesque but she could also satirise some of the theorists' ideas – even as early as when writing Lesley Castle. Marianne is full of romantic enthusiasm and innocence. It is typical that she feels she knows Willoughby fully after just one week. He has encouraged her tastes.
Marianne feels the greatest pain when slighted by Willoughby. At a party, she sees him with another woman (Miss Sophia Grey, heiress to fifty thousand pounds).
Her face is crimsoned over, and she exclaims in a voice of the greatest emotion, 'Good God! Willoughby, what is the meaning of this? Have you not received my letters? Will you not shake hands with me?'