Kim is in a tough spot. He has a very legitimate concern that if he leaves Pyongyang for this meeting in Singapore, his countrymen might not let him return.
Having the locks changed while you're away is a problem many brutal despots face. That's why they don't really travel much.
Yes, but Kim has also been jerking Trump’s chain a LOT. That doesn’t help the cause you identify. My guess is Trump saw the way Kim was yanking his chain and said, “You want to threaten to walk out? Fine. I’m walking out on my own terms. You want to get serious, I’m serious.”
Can Kim really leave, actually leave Pyongyang on anything
other than a train? I believe that they are quite embarrassed
by fact that North Korea has no native transcontinental,
trans-oceanic airline capability that they would rather not show up for the meeting.
True that they can fly to China but that's about it.
Make them fly to Washington DC and watch them whine about that.