President Trump, whose long-distance threats and insults toward North Korea have stoked fears of a nuclear confrontation, brought a message of reassurance to South Korea on Tuesday, moving to bolster an anxious ally as he came within 35 miles of one of the world’s most dangerous borders. Gone were the threats to rain “fire and fury” on North Korea and the derisive references to its leader, Kim Jong-un, as “Little Rocket Man” as Mr. Trump said he saw progress in diplomatic efforts to counter the threat from Pyongyang, adding, “Ultimately, it will all work out.”
