Theory: Bolaire Cannot Tell a Lie
He can forge documents. He can lie by omission. He can phrase things ambiguously. He can mislead. He can state subjective statements and opinions. But he cannot directly say something he knows to be false.
This theory arose in the Halaire Enjoyers server from a moment in episode 24, Good Tidings. Bolaire comes home and checks on Demodus. Brennan describes the way Demodus has decorated the apartment with fun and shiny illusions. Taliesin rolls a die without explaining what it is, then says in a pained voice, "I love what you've done with the place," then immediately takes it back.
This would seem to suggest that Bolaire needs to pass some kind of check in order to be able to lie. He does serve truth, after all. He is the bane of the Trickster: cold hard reality. As Bolaire said, "the weight of reality can crush most things."
It would take a long time for me to go over every single line of Bolaire dialogue to check for lies, but what I can do fairly easily is review scenes where he would have a strong incentive to lie.
When Thaisha Touched Termina
When Thaisha opened the coffin and touched the mask we now know to be Termina, Bolaire understandably reacted very strongly to that, but he didn't want everyone at the funeral to know why. So what did he say?
"I touched the wrong thing many years ago and have had this thing stuck to me ever since. Half the people at the museum have been maimed touching the wrong thing. Whatever else shows up tonight, do not touch it if you don't know where it came from!"
Rating: TRUE. Bolaire touched the wrong thing (a humanoid body) many years ago and has spent his every waking moment since then with a humanoid body stuck to him.
Body-Snatching Aubrus Drime
Bolaire does not lie at any point in this transaction. Aubrus seems to have been promised a "treasure" by Bolaire, and he brought money to pay for that treasure. Bolaire didn't say that "on screen" but it gets a Rating: TRUE. Bolaire did bring an artifact to give to Aubrus: himself.
Lady Cormoray interrupts Bolaire's confession of his nature to the other Schemers, and Bolaire makes the following excuses to try to get her to go away:
"I have my own carriage, but I also say I'm actually putting away some work for the next hour or so that's dangerous to say the least, which is why if you would excuse it."
"I have an emergency. The thing downstairs is volatile and can hurt people so I'm going to need you to leave."
Rating: Misleadingly phrased but TRUE. The work he's doing with the other Schemers is dangerous, and the situation with them downstairs was volatile and could hurt people (indeed, it hurt both Hal and Bolaire.)
The next day, Lady Cormoray returns to the Archanade. She asks Bolaire a pointed question about how Rauwyn died. His response:
"Oh, well, that's the trouble with that one. It was a very, very large piece of destruction. We know where it happened. It was one of the sacred theaters and there were no survivors. It took everything. It's just a crater where that theater used to be. No record, no survivors, and the few people that made whatever weapon that was... died very early in the war."
Rating: TRUE, from Bolaire's perspective. Bolaire does not consider himself or his siblings to be people, and by that metric, nobody survived the Panto.
"Have you ever met Halandil Fang?"
Rating: BORDERLINE. "Few" is an ambiguous word that's hard to pin down. "Met" is also ambiguous, in that it's something you do with someone you don't already know well. I think there is enough wiggle room in these words to say Bolaire is just about telling the truth.
Playing Cards with KIng Gus
Bolaire has a Disguise Self up and he's pretending to be someone else while playing cards with King Gus in episode 21. Surely he must have lied, right? Wrong!
"And what might I call you, my good man?"
"Oh, you can call me Delex."
Rating: TRUE. Bolaire didn't say his name was Delex, he said "you can call me Delex."
"Antiquities? Fascinating. That's a very fascinating trade. Do you work in a private shop or with a collection?"
"Mostly with a collection. Although, I'm in between collections at the moment. Things are a bit topsy-turvy, times being what they are. But I do a little bit of business, mostly above board."
Rating: TRUE. I'm particularly awed at Tal's wordplay with "in between collections at the moment." Bolaire is literally in between collections because of the big switch of artifacts between the Lloy Wing and the Selodyne Wing.
"I have a friend at the museum, if you're ever in the mood to take a look at a few things. I have many friends there. But just look up Bolaire Lathalia, I think it'll be worth your time if you ever want to see things around."
Rating: TRUE. Bolaire does have friends at the museum. He never said his friend's name was Bolaire Lathalia.
Everything Bolaire says in this very tense sequence with Lady Cormoray is inarguably true. The only bit that's borderline is this exchange:
"What motivated you to try and steal the blades?"
"I was attempting to return them to their owner."
Rating: BORDERLINE, but can be fairly easily interpreted as true. Either a) Bolaire fully intends to return the pariah blades to the Lloys once Thaisha returns to Dol-Makjar, or b) Bolaire considers the pariah blades to belong to all the Rungjani, and therefore bringing the blades to the people's theater is bringing them to their owner.
It's also worth noting that Taliesin repeatedly says throughout that tense sequence things like "like anything I do, it's lies of omission" and "that's basically true", as if reassuring himself and the viewer that Bolaire is not lying.
The only point where I could find any straightforward, clear falsehoods stated by Bolaire was in the flashback, the episode 13 cold open. Bolaire says this about Castep when one of the soldiers asks why he's watching the play:
"No, he's enjoying it so much. I was just letting-- I was letting him through. He seems to want to watch."
Rating: FALSE. It's possible that Castep liked the play, but Bolaire was not "just letting him through."
"Yeah, it was-- It was so odd."
"You got the mask off on your own."
"It was-- It was like it was afraid, too. It was worried about what it was going to become, and it let me put it to sleep."
Rating: FALSE. Even if we stretch so far as to say that Bolaire was referring to Castep as "it", Castep did not let Bolaire put him to sleep; Bolaire hadn't even fully stolen Castep's body at this point.
Bolaire's nature seems to be different when he's being a warlock patron to other people vs. to himself, and he is quite different now to who he was then. It's possible that before Bolaire made that decision to run away and become his own mask, he was able to lie more easily.
If anyone can think of any other times in the show when Bolaire clearly stated a falsehood, please let me know. I'm just one nerd and I can't go over every single Bolaire line with a fine-toothed comb, but I do think I might be onto something here!