Speaking before departing Washington, Trump played down the role China could have in resolving the conflict, which has continued to block maritime traffic through a waterway that usually carries one-fifth of the world's oil supply.
"I don't think we need any help with Iran. We'll win it one way or the other, peacefully or otherwise," he told reporters on Wednesday.
More than one month after a tenuous ceasefire took effect, US and Iranian demands to end the war remain far apart.
Washington has called for Tehran to scrap its nuclear program and lift its chokehold on the strait, while Iran has demanded compensation for war damage, an end to the US blockade and a halt to fighting on all fronts, including in Lebanon, where Israel is battling Iran-backed Hezbollah.
Trump has dismissed those positions as "garbage".
Iran, meanwhile, has firmed up its control over the Strait of Hormuz, cutting deals with Iraq and Pakistan to ship oil and liquefied natural gas from the region, according to sources with knowledge of the matter.
Other countries were exploring similar arrangements, sources said, in a move that could normalise Tehran's control of the waterway on a more permanent basis.
The Trump administration said on Tuesday that senior US and Chinese officials had agreed in April that no country should be able to charge tolls on traffic through the region, in an effort to project consensus on the issue ahead of the summit.
China, a major buyer of Iranian oil that maintains close ties with Tehran, did not dispute that account.
As the costs of the conflict mount, Trump said Americans' financial struggles were not a factor in his decision-making on the war.
Data released on Tuesday showed that US consumer inflation accelerated in April, with the annual rate posting its largest gain in three years as food, rent and airfares rose.
Asked to what extent the economic strain on Americans was motivating him to strike a deal, Trump replied: "Not even a little bit."
"The only thing that matters, when I'm talking about Iran, they can't have a nuclear weapon," Trump said before leaving for China.
"I don't think about Americans' financial situation ... I think about one thing: We cannot let Iran have a nuclear weapon. That's all. That's the only thing that motivates me."
The remarks are likely to draw scrutiny as cost-of-living concerns remain a top issue for voters before November's midterm elections.
The conflict is weighing heavily on global energy markets.
Global oil supply will fall by about 3.9 million barrels a day across 2026 and undershoot demand due to disruptions caused by the Iran war, the International Energy Agency said on Wednesday, with more than one billion barrels of Middle East supply already lost.
Brent crude futures edged down slightly to $US107 per barrel after a three-day rally driven by the Hormuz deadlock.
US Central Command said the aircraft carrier Abraham Lincoln was in the Arabian Sea enforcing a maritime blockade, redirecting 65 commercial vessels and disabling four others.
Surveys show the war is unpopular with US voters less than six months before nationwide elections.
Iranian officials remain defiant.
A Fars news agency report cited an Islamic Revolutionary Guard Corps official as saying Iran had expanded its definition of the Strait of Hormuz into a zone stretching from the coast of the city of Jask in the east to Siri Island in the west.
In Tehran, the Guards held drills "centred on preparation to confront the enemy", state TV reported.
