By the end of the meal, only Mason Han and Hannah Du remained. Both parents had soon excused themselves with prior engagements. Neither of the young people asked a single follow-up question—they were clearly used to it. Wiping her fingers with a wet napkin, Ms. Du asked politely first: "Mr. Han, how many times have you been here?" It sounded as though she were asking how often Mason Han had eaten at this restaurant. In fact what she meant was clearly how many blind dates he had been on. "Lost...