The following are my opinions only:

"To no creature had it been revealed, where secresy was possible, except to Elizabeth; and from all Bingley's connexions her brother (Darcy) was particularly anxious to conceal it, from that very wish (that Bingley would marry Georgianna) which Elizabeth had long ago attributed to him (Darcy), of their (Bingley's connexions) becoming hereafter her own (Georgianna's connections, i.e. through marriage, Bingley's connections would become Georgianna's). He (Darcy) had certainly formed such a plan (to get Georgianna married to Bingley), and without meaning that it should effect his endeavour to separate him from Miss Bennet, it is probable that it (Darcy's plans to get Bingley and Georgianna together) might add something to his lively concern for the welfare of his friend."