Donald Trump has claimed China will ease trade barriers "because it is the right thing to do", and said Washington and Beijing can settle disputes that have rattled financial markets, consumers and businesses.
A tweet from the president did not explain why he is optimistic about resolving an escalating trade clash between the world's two biggest economies.
Mr Trump said he and Chinese President Xi Jinping "will always be friends, no matter what happens with our dispute on trade".
The US bought more than $500bn in goods from China last year and is planning or considering penalties on $150bn of those imports.
The US sold about $130bn in goods to China in 2017 and faces a potentially devastating hit to its market there if Beijing responds in kind.
China has pledged to "counterattack with great strength" if Mr Trump follows through on his latest threat to impose tariffs on an additional $100bn in Chinese goods - after an earlier announcement that targeted $50bn.
The Trump administration is also pushing for a crackdown on what it says is China's theft of US intellectual property.
Conflicting messages about the trade fight have come out in recent days from some senior members of Mr Trump's team.
Treasury secretary Steven Mnuchin said he was "cautiously optimistic" that the US and China could reach an agreement before any tariffs went into place, but he also said "there is the potential of a trade war".
The new White House economic adviser, Larry Kudlow, said the US is "not in a trade war" and that "China is the problem. Blame China, not Trump."