U.S. President Donald Trump said on Thursday he "probably" has a very good relationship with North Korean leader Kim Jong Un, a change in tone for Trump after exchanging insults with Kim over Pyongyang's nuclear and missile programs.Trump has derided the North Korean leader as a "maniac" and referred to him as "little rocket man." Kim has responded by calling the U.S. president a "mentally deranged U.S. dotard." "I probably have a very good relationship with Kim Jong Un," Trump said in an interview with The Wall Street Journal. "I have relationships with people. I think you people are surprised." Kim has warned the United States that he intends to build a nuclear arsenal capable of hitting the United States, prompting threats of military action by Washington. Asked whether he has spoken with the North Korean leader, Trump told the newspaper: "I don't want to comment on it. I'm not saying I have or haven't. I just don't want to comment." In November, Trump said while on a trip to Vietnam that becoming friends with Kim "might be a strange thing to happen but it's a possibility." Kim, in a speech last week, said the "nuclear button is always on my desk," prompting Trump to respond in a tweet that his nuclear button is "a much bigger & more powerful one than his, and my Button works!" In the Journal interview, Trump suggested his combative tweets are part of a broader strategy. "You\u2019ll see that a lot with me," he said, "and then all of the sudden somebody\u2019s my best friend. I could give you 20 examples. You could give me 30. I\u2019m a very flexible person."Trump told the newspaper a decision by the United States and South Korea to postpone military exercises until after next month's Winter Olympics in South Korea "sends a good message to North Korea." North and South Korea held their first talks in two years on Tuesday. Trump told a news conference in Washington on Wednesday the United States would be willing to speak to Pyongyang "under the right circumstances."