“In a few days Mr. Bingley returned Mr. Bennet's visit, and sat about ten minutes with him in his library. He had entertained hopes of being admitted to a sight of the young ladies, of whose beauty he had heard much; but he saw only the father” (3)

I have to agree with others that it is unlikely Mr. Bennet thought Bingley would be unpleasant. By the assembly they have already met twice and he probably noticed during Bingley’s visit to Longbourn (above) he would not have objected to meeting the ladies. Mr. Bennet probably got a chuckle out of not taking him to them. I grant Mr. Bennet understands his daughter’s prospects but why would he think Bingley disparages connections to trade? I can’t think Bingley would give that impression because we know that he does not feel that way: “If they had uncles enough to fill all Cheapside," cried Bingley, "it would not make them one jot less agreeable” (8). If Mr. Bennet thought Bingley was a truly hopeless object it would be more in character for him to let Mrs. Bennet continue hoping for she is sure to be a source of amusement in such an endeavor. I do agree Mr. Bennet could not convince Mrs. Bennet of any truth she was not already disposed to embrace. (:D)