Here is an article in the New York Times about the image makeover that President Moon has helped Kim Jong-un achieve over the past year. I think this below passage from the article shows the example of either mass mental illness or effective control of the ROK media by the Moon administration if 77% of South Koreans actually think the Kim regime is trustworthy:
The summit meeting mainly rehashed old inter-Korean agreements that had never been kept, producing only a vaguely worded commitment to denuclearization and peace. But the images made the event a success, providing momentum for warmed ties between the two countries and redefining Mr. Kim in the eyes of many South Koreans.
The next morning, a South Korean newspaper filled its front and back pages with a photograph showing Mr. Moon and Mr. Kim crossing the border hand in hand. Mr. Kim, formerly vilified as the region’s most dangerous leader, was considered “trustworthy” by 77 percent of South Koreans following the meeting, according to a survey by the Korea Research Center.
“Chairman Kim’s popularity has risen rapidly among South Koreans, and so have the expectations,” Mr. Moon told Mr. Kim last month when they met for the second time at Panmunjom. He said the summit meeting especially strengthened Mr. Kim’s image among younger South Koreans, who have shaped their views of North Korea through the past decade of inter-Korean tensions and have become increasingly skeptical of reconciliation, much less reunification, with the North. [New York Times]
What this means is that when Kim Jong-un eventually renegs on getting rid of his nuclear weapons he will blame the Americans and the Moon administration will make sure that 77% of South Koreans will agree with him.