By reaching a "Phase One" trade deal with China, President Donald Trump is probably playing games with China for 2 major reasons. First, Trump knows well that China is going to violate the agreement. The US will then have every justification to penalize and even put an end to China, which is now the single biggest national security threat to the USA, as put by Senator Marco Rubio and agreed by Security of State Mike Pompeo, by imposing an over 40% tariff on all China goods amongst other harsh measures. Second, with the trade deal, Trump can counteract the impact of the impeachment and consolidate his rural voter base in agricultural states.
China is most unlikely to abide by the requirements of the trade deal. For to stop stealing US intellectual property, exercising forced technology transfer, intervening in foreign exchange markets, and manipulating RMB will deprive China of its major means of getting rich and powerful. (On top of this, Section 5 of the recently enacted Hong Kong Human Rights and Democracy Act prevents China from using Hong Kong to import embargoed sensitive products from the USA.) To open up its financial services market will put an end to the CCP rule. To double purchases of U.S. agriculture products will destroy China's agricultural economy.
China seldom keeps its words anyway; its violation of its WTO obligations and its dismissal of the Sino-British Joint Declaration as an outdated document are cases in point.