"I'm aghast we trust the People's Republic of China more than we trust the White House," Cramer said on "Squawk Box." "The predominance of coverage this morning is that the president is lying. I'm not willing to say that he's lying. We can doubt him, but in the end we're doubting a guy that didn't want the market to crash."
Cramer was referring to Trump's comments at the G-7 summit Monday in France, where he said Beijing is ready to reenter negotiations and begin serious talks.
"China called last night our top trade people and said 'let's get back to the table' so we will be getting back to the table and I think they want to do something," Trump told reporters.
At a later press event, Trump said he didn't want to talk about phone calls, saying that talks between U.S. and Chinese trade officials have been taking place at the highest levels.
However, the editor-in-chief of the Global Times, a tabloid controlled by the Communist Party of China, tweeted that Trump was "exaggerating."
"The two sides have been keeping contact at technical level, it doesn't have significance that President Trump suggested," he said in a tweet Monday. "China won't cave to U.S. pressure."
Cramer added that Chinese government officials "haven't necessarily been square and honest," stressing that people need to take Trump "seriously."
Investors should trust that "Trump is going to be determined to weaken the Chinese economy," the "Mad Money" host concluded.
On Friday, after China announced retaliatory tariffs in response to additional upcoming U.S. duties, Trump said he will boost the rate to 15% from 10% on levies set to start Sept. 1 and Dec. 15. He also said he will raise the existing tariff rate on Chinese products to 30% from 25%, starting Oct. 1.