⟩ How do you prepare for a sale? Can you describe your most difficult client? How did you handle this client and were you able to make the sale? If you do not sell to a particular prospective client, would you plan to try to sell to them again? How do you change your approach?
Keep in mind that selling is a positive and outgoing, self-motivating field of employment. Conveying that one has these attitudes will bring success.
At the same time, you may wish to express this point. Your time is valuable yet limited. Time spent on convincing an uninterested client could be perhaps better invested in a new potential client.