What he means is that the so called old inexperienced Khamenei can't be fooled by the sweet talks of a war criminal like Obama!
So for example when Obama threatens Iran with nuclear attack on daily bases (all options on the table), when he applies the toughest sanctions against Iran (what even Bush didn't), when orders to assassinate Iranian scientists, when starts a cyber war against Iran, when founds and supports a dozen of terrorist groups around Iran (ISIS was just one of them), and while actively seeks regime change in Iran, in this situation, a so called experienced politician ( in his eyes) should forget these and see them as just a misunderstanding!
However, what he forgot is that if two fools like Rouhani and Zarif actually called west's hostility against Iran a misunderstanding and trusted them and signed a sh!ty deal (worst than their own sh!t), they were playing within Khamenei's plan to give Iranian a lesson, that signing a deal with a terrorist (Obama) is as useless as it should be.