(CNN) US President Donald Trump looked back at a turbulent first 100 days of his presidency in a wide-ranging interview Thursday, taking in a variety of topics to the standoff on the Korean peninsula to his new friendship with China's President Xi Jinping.

Trump on the presidency

Reflecting on a first 100 days in office that has featured no major legislative wins and low approval ratings, Trump said he thought the job would be easier

"I loved my previous life, I loved my previous life. I had so many things going," Trump said. "I actually, this is more work than my previous life. I thought it would be easier."

He later added, "I do miss my old life. This -- I like to work. But this is actually more work."

Trump also said he misses his pre-presidency freedom -- as well as getting behind the wheel.

"And, while I had very little privacy, in my old life because, you know, I've been famous for a long time. I really -- this is much less privacy than I've seen before. This is, you know, something that's really amazing. At the same time, you're really into your own cocoon because there's such massive protection, that you really can't go anywhere."

Trump on North Korea

In the interview Trump warned not to discount the chance of a military conflict with North Korea even as his Secretary of State seemed to leave the door open for talks.

"There is a chance that we could end up having a major, major conflict with North Korea," Trump told Reuters, amid an ongoing standoff over Pyongyang's nuclear and missile programs.

He said the reclusive nation represented the biggest global concern at the moment, but did suggest he would be willing to resolve the situation through talks.

"We'd love to solve things diplomatically, but it's very difficult," he said.

He seemed to show some sympathy with the difficulties that has Kim Jong Un faced running the country.

"He's 27 years old. His father dies, took over a regime. So say what you want but that is not easy, especially at that age," he said, although he misjudged the dictator's age by a few years. Kim is estimated to be in his early 30s.

"I'm not giving him credit or not giving him credit, I'm just saying that's a very hard thing to do. As to whether or not he's rational, I have no opinion on it. I hope he's rational," he said.

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Trump on Xi

"I believe he is trying very hard. He certainly doesn't want to see turmoil and death. He doesn't want to see it. He is a good man. He is a very good man, and I got to know him very well.

"With that being said, he loves China and he loves the people of China. I know he would like to be able to do something, perhaps it's possible that he can't," Trump said.

He said he would consult with the Chinese leader before talking to Taiwan's leadership on the phone.

"My problem is that I have established a very good personal relationship with President Xi," Trump said. "I really feel that he is doing everything in his power to help us with a big situation," he said, referring to the situation on the Korean peninsula.

"So I wouldn't want to be causing difficulty right now for him. So I would certainly want to speak to him first."

JUST WATCHED Trump appears to flip-flop on China, Russia Replay More Videos ... MUST WATCH Trump appears to flip-flop on China, Russia 02:33

Trump on ISIS

"I have to say, there is an end. And it has to be humiliation," he said, expressing his disbelief in the brutal methods the jihadist group employs.

"We are really eradicating some very bad people. When you take a look at what's going on with the cutting off of the heads. We haven't seen that since medieval times. Right?"

But he suggested there was "an end" to the group's continued existence.

"Otherwise it's really tough. But there is an end," he added, but did not elaborate on how to reach that endgame.

He criticized coalition partner Saudi Arabia in the interview, suggesting the oil-rich kingdom was not treating the US "fairly."

"Frankly, Saudi Arabia has not treated us fairly, because we are losing a tremendous amount of money in defending Saudi Arabia," he said.

Trump on NAFTA

Trump walked back from one of his signature campaign promises to exit the North American Free Trade Agreement, instead saying that his administration is ready to renegotiate the treaty

"I get a call from Mexico yesterday, 'We hear you're going to terminate NAFTA.' I said that's right. They said, 'Is there any way we can do something without you -- without termination?' I said, 'What do you want to do?' He said, 'Well, we'd like to negotiate.' I said we'll think about it," he said in the interview.

"Then I get a call, and they call me, I get a call from (Canadian Prime Minister) Justin Trudeau and he said, 'We'd like to see if we can work something out,' and I said that's fine. Because I've always -- I've been very consistent. It's much less disruptive if we can make a fair trade deal than if we terminate."