@EmmaLory I dont think that US will attack Iran and Trump only gave this statement to assert his authority, and keep Iran guessing about his next move. If he really wanted to start a war with Iran then he could have done it in June 2019, when he had ordered for rockets to be fired on Irans soil but as we all know he didnt execute that plan hence I believe there will be no war between the two nations.
Source:
https://www.nytimes.com/2019/06/20/world/middleeast/iran-us-drone.html