SEOUL, South Korea — As South Koreans prepare for their president to meet Kim Jong-un on Friday, many are left scratching their heads about the motives of a North Korean leader who has abruptly pivoted from threats of nuclear annihilation to offering warm peace overtures.

Many older South Koreans feel they have seen this before: a member of the Kim dynasty gets rewarded for coming to the bargaining table, the talks sputter, and the North goes back to its old ways. But this time, the North’s 34-year-old leader comes equipped with a fearsome nuclear stockpile as he walks into the summit meeting with the South’s president, Moon Jae-in.

“The North Koreans are cheating again, putting up this show so they can buy time and ease sanctions, never intending to abandon their nuclear weapons,” said Kim Chang-guk, 73, who joined other older citizens in downtown Seoul on a recent weekend to protest the inter-Korean summit meeting. “I would rather believe a woman who has given birth to a baby and still insists that she is a virgin than Kim Jong-un.”

The peace overtures come after Mr. Kim kept the Korean Peninsula on the edge last year, testing missiles and what he said was a hydrogen bomb. He claimed to have a “nuclear button” on his desk that could launch missiles that could hit anywhere in the mainland United States.