President-elect Donald Trump had his first face-to-face meeting with a foreign leader Thursday evening, but very little is known about what the two men discussed, or how far Mr. Trump went to put a key U.S. ally at ease over remarks made on the campaign trail.

Mr. Trump met Japanese Prime Minister Shinzo Abe at the Republican billionaire’s home in Manhattan, and whatever was said, it seems to have been enough to convince Abe that the incoming U.S. leader is “trustworthy.”

The only other people in the room -- judging from photos released by Trump himself of the encounter in an ornate room at Trump Tower -- were Abe’s translator and three of Trump’s most trusted confidants; his daughter Ivanka, her husband and close Trump adviser Jared Kushner, and Lieutenant General Michael Flynn (ret.), whom Trump has tapped to be his national security adviser.

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“Alliances cannot function without trust. I am now confident that President-elect Trump is a trustworthy leader,” said Abe after the meeting, which he described as a “candid” session held in a “warm atmosphere.”

Mr. Trump said during his campaigning for the presidency that he could require Japan to pay more to remain under the umbrella of U.S. security -- backed up by America’s nuclear weapons -- which remains a cornerstone of America’s Asia policy in the face of an increasingly assertive China.

He suggested that Japan might itself have to acquire a nuclear armament – a notion which could completely disrupt the balance of security in Asia and set off an arms race among neighbors who already distrust one another.

The president-elect has yet to articulate a clear defense policy toward China and the region as a whole, unsettling officials in Tokyo and South Korea, who have watched China test the limits of its boundaries at sea and throw around its military might with increasing disregard for the tenuous balance of Asian security.

Mr. Trump himself said nothing of substance after meeting Abe, posting on Facebook only that it had been “a pleasure to have Prime Minster Shinzo Abe stop by my home and begin a great friendship.”

According to the Reuters news agency, Abe gave Mr. Trump a golf driver, and the Japanese leader was given some golf apparel.