Care to expound?
Trustworthy is not one of the common adjectives I see used to describe Trump.
He's a fighter, or a great deal maker, or a stable genius, 4d chess player, a master troll, tells it like it is, or many other things.
Some of those I don't particularly value, some I don't take issue with.
Maybe you're just setting an incredibly low bar with the comparison to previous presidents. However I rarely see him described as trustworthy - honest, reliable, dependable, loyal, etc.
It's simple. What Trump said he would do*, he has done or tried to do while fighting both the Democrats and the establishment Republicans.
He said he'd go after the unfair trade deals the US has been a part of. (Whether you think they were unfair or not, that's what he promised.) He has. He renegotiated NAFTA and has been putting China over a barrel for their years of underhanded tactics.
He said he'd repeal Obamacare. He's done everything possible, against members of his own party, even, to do that. Your avatar ensured he put a knife in that as his last act of a spiteful, dying man.
He said he'd build the wall. He's done everything possible to fulfill that one, as well, fighting against his own party, often to do it.
He said he'd appoint strict constitutionalists to the bench. He and Sen. McConnell have been absolutely awesome on that.
He promised he'd put an end to the previous administration's targeting of religious dissenters. He promised he'd bring back jobs. He promised he'd get us to 3% growth. ("Where's his magic wand?" cried Obama.)
I'm not sure what he said about foreign wars, but he's at least avoided getting us involved in any new ones, so that's a plus whether it was a promise or not.
Honestly, I expected him to knife conservatives in the back and govern as a liberal. Instead, he's been amazingly consistent with what he promised.*
*what he said he would do, once normal people who understand braggadocio and puffery have made the necessary discounts to the promises. For example: "HE SAID HE'D MAKE MEXICO PAY FOR THE WALL!!!" No one who heard that boast thought it was a serious one and no one who actually wants the wall cares that he make Mexico pay for it. It was simply bluster for effect.
Normal people who hear such bluster already know how to deal with it and easily take it into account when hearing such a person. Sometimes you hate the braggart and sometimes you like him, but people deal with braggarts all the time. What they find much more offensive is someone who lies to your face and then claims he was
technically correct because he was meaning "Y" while implying "X" and, well, it's your fault you didn't pick apart his weaselly wording to pin him down on what he was actually saying while purposely implying something different to mislead you.
THAT is why people don't have a problem with Trump's "lies", because the weaselly lawyers in DC think he's just blatantly lying, the rest of the country finds him a breath of fresh air compared to the above that politicians do.