In the opening minutes of the Trump-Kim summit it will become very obvious that Trump will withdraw because Kim does not immediately lie down and offer his entire nuclear arsenal in exchange for reunification with South Korea.
Kim has already achieved what he wants – a meeting with the US President. He will offer an exchange of denuclearisation – he will give up his weapons when the remaining nuclear powers give up their and he will then demand a set on the Security Council.
Trump will then depart. Kim will have made his point.