In Sense and Sensibility, how does Jane Austen present Willoughby's character early in the novel and do her descriptions give the reader any clue...

When we first meet Willoughby, he is described as carrying
Marianne home in his arms. He is described as gallant, heroic, and handsome, the picture of an
ideal romantic hero. This early description certainly does not give any clue to his true nature.
When he first calls on Marianne, she sees that he is sincere and straightforward, with a happy,
energetic nature. She also learns that he is fond of dancing and music and that, "Their taste was
strikingly alike. The same books, the same passages were idolised by each." He is also described
as being as equally passionate about interests as Marianne. Furthermore, through his daily
visits, Marianne and the family soon learn that he is polite, intelligent, imaginative, and has
"lively spirits, and open, affectionate manners" (Ch. 10).

None of these
characteristics give us any clue to his extravagant nature and want of principles. However, we
know from earlier descriptions of both Elinor and Marianne that Elinor has sense, and Marianne,
while she may have it too, doesn't use it. Therefore, Austen very carefully prepped us to very
soon understand that Marianne is wrong. While she is right about these positive traits and right
to think they are admirable, she is wrong to think that they are all that is needed. They are not
enough. We actually need these qualities plus principles
and sense, just like Colonel Brandon has.