WASHINGTON — The self-proclaimed master dealmaker is facing doubts from multiple corners as he prepares to negotiate with Kim Jong Un.

Ahead of President Donald Trump’s landmark summit next week with the North Korean leader, U.S. allies and many Republicans are raising concerns that he may impulsively give in on issues they say should be deal-breakers for the United States. Ambiguity about exactly what “denuclearization” must look like has left some wringing their hands, while others fear he may yield on a longtime North Korean wish that the U.S. withdraw some or all of its military presence on the Korean Peninsula.

There are worries from some quarters about Kim’s intentions and his willingness to actually follow through on any commitment he might make in Singapore.

“My suspicion remains that he is going to try to get as much sanctions relief as possible without having to give up his weapons,” said Sen. Marco Rubio, R-Fla.

Rubio, who applauded Trump’s now-reversed decision to cancel the summit, said at the time that it was apparent that Kim’s goal “was either to gain sanctions relief in exchange for nothing or to collapse international sanctions by making the U.S. appear to be the unreasonable party.”