it is the responsibility of host/hostess to find topics of conversation that will interest the guest & not make them uncomfortable, not that of the guest to provide the hostess with whatever information she is seeking. Emma should be the one to introduce a neutral or general topic once she sees that Jane does not wish to divulge information about her other friends. As Mr. Knightly remarks the next day, Jane's reserve is the product both of her diffidence and discretion, & he surmises that the diffidence could be overcome with greater familiarity but that Emma should not try to overcome Jane's discretion. Jane's diffidence contributes to her not attempting to direct the conversation--that is Emma's prerogative.