In Pride and Prejudice, Jane is described as an exquisite beauty, the prettiest of the Bennet sisters. She would be the most attractive to potential suitors. Jane also has an easy manner about her, not too smart as to insult a candidate who would become her husband.
Jane is a lady, she is graceful and pleasant in her manner. It is hard to dislike Jane, she is the type of woman that men can admire from a distance and when they get up close they discover that not only is she beautiful, but sweet, kind and easy to love.
Lydia is very outgoing, has a good sense of humor and is very amiable. Lydia is not a serious individual, all she is interested in is having fun. This quality might be appealing to young men like herself who are also looking for fun. Lydia seems to lack a moral core which could also be attractive to men, especially men like Wickham. Lydia is spontaneous, she elopes with Wickham, well they are not actually married, she runs away with him and has no qualms about being alone with him. She does not realize that she is violating her family's honor by her behavior.
On the contrary, Lizzie, although pleasant looking her demeanor is dominated by her wit, intelligence and ability to hold her own in a conversation with any man. Lizzie Bennet is a complex woman, educated and refined, but not easily wooed. She is not as easy to love as Jane and not silly like Lydia. In fact, Lizzie is somewhat unapproachable. She is serious and steady, not given to flights of fancy like Lydia. But also not like Jane who appeals to men and is admired so quickly and easily.
Lizzie is looking for something more in a man, a husband that will regard her intelligence as an asset and not a detriment. She does not want to hide her education, so that man who looks to marry Lizzie will have to be very secure in his own knowledge and not feel threatened by her. Nor can her potential husband be intimidated by her sharp wit or caustic sense of humor that is tinged with irony.