What's the toughest 'no' you've had to turn into a yes?

In sales and roleplay training, the whole skill is turning a no into a yes — the third attempt, the fifth objection, twenty minutes in. Our Halloween demo plays with exactly that: our special guest has one candy, and she won't just hand it over. What's the toughest no you've had to turn, and what finally worked? We're launching on Product Hunt Tue 3 Nov.