Colonel Brandon's partiality for Marianne, which had so early been discovered by his friends, now first became perceptible to Elinor, when it ceased to be noticed by them. Their attention and wit were drawn off to his more fortunate rival; and the raillery which the other had incurred before any partiality arose, was removed when his feelings began really to call for the ridicule so justly annexed to sensibility. Elinor was obliged, though unwillingly, to believe that the sentiments which Mrs. Jennings had assigned him for her own satisfaction, were now actually excited by her sister; and that however a general resemblance of disposition between the parties might forward the affection of Mr. Willoughby, an equally striking opposition of character was no hindrance to the regard of Colonel Brandon. She saw it with concern; for what could a silent man of five-and-thirty hope, when opposed by a very lively one of five-and-twenty? and as she could not even wish him successful, she heartily wished him indifferent. (10.11)

The contrast between Colonel Brandon and Willoughby is painful – it demonstrates the prejudices rampant in the society Austen wrote about, that are still going strong in our own. Despite the fact that Willoughby is hiding a dastardly past (which everyone finds out about soon enough), his outer charm and pizzazz is enough to make him more successful than good, solid, dependable Colonel Brandon.