In a statement carried by state media, Kim Yo Jong said she doesn’t deny the personal relationship between her brother and Trump “is not bad.” But she said if their personal relations are to serve the purpose of North Korea’s denuclearization, North Korea would view it as “nothing but a mockery.”

The powerful sister of North Korean leader Kim Jong Un dismissed U.S. intent to resume diplomacy on North Korea’s denuclearization, saying Tuesday the North flatly opposes any attempt to deny its posi...