Come now, Donuel. ;-) That's being a bit nasty. The Japanese ambassador in December '41 had been sent a text (in code) specifically worded as an official declaration of war from Japan on the USA. He was instructed to give it to Cordell Hull at a specific time (shortly prior to the attack going in at Pearl Harbour) so that the state of war would officially exist prior to that hostile act. He failed to do so on time, because his incompetent office staff had so much trouble decoding the message and laboriously typing it out a letter at a time that they didn't have it translated in time for him to deliver it on schedule.

This utterly humiliated the Japanese ambassador, and it horrified Admiral Yamamoto when he found out about it, because he knew the American nation would never forgive a "sneak attack" launched prior to the declaration of war. (In fact, they'd never have forgiven any kind of major attack like that, but Yamamoto, like all Japanese, had a rather medieval concept of honor, so it was a major concern to him at least.)

I don't see how any of the above translates to the Japanese ambassador being untrustworthy. He did what his job required, and it was not his intention to deceive the USA regarding Japanese intentions, but to deliver that message as ordered to...and on time.

The attack was scheduled to occur about half an hour after delivery of the message, but the message didn't get translated on time.

The Japanese ambassador was a man put in an impossible position by his own government and his poorly trained office staff, and he should not be blamed for what happened. (In any case, both the American and Japanese governments knew darned well that war was coming between them...and very soon. And the military on both sides knew it too. There was really no doubt of it. The only question was, on which day would it happen? Only....the general public in both countries was not informed about that.)

You could say that the people who were tricked were the ordinary citizenry.   In both countries. They (and the ordinary servicemen on the Allied side) were the ones who got blindsided.

None of that was the Japanese ambassador's fault.