Why did the Bennett woman have to accept lady Lucas description of Mr. Bingely

The Bennett women could not get information out of Mr. Bennett so they had to rely on Lady Lucas for information on Mr. Bingley.

They attacked him in various ways—with barefaced questions, ingenious suppositions, and distant surmises; but he eluded the skill of them all, and they were at last obliged to accept the second-hand intelligence of their neighbour, Lady Lucas.