My expectation for this sudden positive development from Trump is only for two days; I'll profit from the rebound and then exit. What's most likely going on is that Iran has been divided since the Khamenei era into pro-American/surrender factions and hardliners/confrontational factions. Trump is most likely talking to the pro-American "leader." The current true leader of Iran, Khamenei's son, represents the hardliners. He holds most of the control over Iran. If he doesn't relinquish control, there's nothing that can be done.