Trump promises a deal with Tehran if he wins elections

Donald Trump, President of the United States, said he would strike a deal with Iran if he wins the election.

He said this during a White House briefing:

“Iran is suffering, unfortunately. I don’t want them to suffer. Their economy collapsed. Their GDP will be minus 27%, no one has heard of such a number. This is possibly a record. They really want to make a deal”. 

How “generous” of him. Why, in the case of such unprecedented “nobility”, Trump did not talk about the deal before? Why is it so necessary to wait for the elections? It’s good that “generosity” fits so well into the election race.