That was another of his thousands of lies. He had said several times that he was close to signing a deal with China -- even though China never said any deal was close. That had been enough to send the market up, because American businesses and investors want a deal to be done. They want the trade war to be over before it wrecks the economy.
The truth is that Trump would love to sign a deal. He do it tomorrow if he could. He's not the one delaying a deal. China is.
It has become obvious lately that China has decided to wait until the next election is over to get serious about any new deal. They think there's a good chance that Trump will be defeated in the next election, and a new president might end Trump's trade war on better terms for both countries.
Trump was just trying to save face with his comment about wanting to wait.