While Jin was unaware as to the reason of his sudden promotion, it put a strain on his relationship with Sun. Jin's first assignment was to "convince" a government official to overlook the violating environmental regulations caused by one of Paik's factories. Jin gave the official's puppy to Sun as a gift, but on the second visit, Jin violently beat him to prevent a hitman from killing him. Jin returned home covered in blood, but refrained from telling Sun about the work her father ordered him to do. Despite their problems, Jin and Sun tried to conceive children. However; after a visit with a fertility doctor, Jin grew angry upon learning that Sun could not conceive, and accused her of knowing all along. The doctor later admitted to Sun that the opposite was true, that Jin was the one who was sterile. The doctor was afraid to reveal this to Jin for fear of retribution, as he knew of Jin's work for Mr. Paik. Later, Paik ordered Jin to kill Jae Lee, though he did not reveal to Jin the reason (he was having an affair with Sun). Following orders, Jin confronted Jae Lee at his hotel room and violently beat him. Instead of killing him; however, Jin told him to leave the country and never return. Upon returning to his car, Jin was startled when Jae Lee landed on his car after jumping from his hotel room as a supposed act of suicide.