Tibex (Tibex Escriva, now) does not trust Theopho of the Runes. If he was going to start trusting tallfolk, Theopho might be one, and he does genuinely like him, and he's pretty sure if he did trust Theo then that trust wouldn't be betrayed. But still, he doesn't.
He's known the man since he was a baby, literally, and while the boy's far better at hiding his intentions since he returned from his foreign excursions, he has tells, most of the the same he had as a child when he was completely awful at hiding his mind, and even today he couldn't keep a secret from Tibex for months, unless it was his first priority, and maybe not then. Tibex was his sole slave for three years, and his parent's slave mostly devoted to taking care of their son for at least five years before that. There are very few secrets Theo has from Tibex, except those he kept professionally and hid from everyone, even the crown, which barely affected his actions. And not all of those; Theopho made little effort to conceal that he thought slavery was pointless counterproductive injustice and would free Tibex if he could, even when that was a crime.
The last time he ever beat Tibex was when he was seven, and he gave up partway through and ran away. In three years, he slapped Tibex four times, all in public, and apologized in private for three of those, saying he needed to keep up appearances. There are good reasons why he likes his former master, rather than the man's parents, who were his masters the rest of his life.
Theopho trusts Tibex. He's pretty sure of that. But he doesn't reciprocate, and if he doesn't mention that to his former master, well, that's just good sense. And a probably-Good impulse to spare his feelings, but hey, that's legal now. And it's not like they tried that hard to damn the 'slips', honestly. They were beneath notice; moral patients, but not moral agents.
(Tibex can read, and write, quite well. Theopho gave him significantly less work than he could take, and free use of his bookshelf when he wasn't using it, and later gave him work copying letters and taking notes from the books. So he went from 'read slowly out loud' to 'read quickly and barely move his lips, and write nearly as well' over the last few years.)
And so Tibex keeps his secrets, even though he is a free man with papers and everything and could turn on him with no legal consequences. He doesn't really want to, and it hasn't seemed necessary, and Jamisa doesn't know the man as well as he does but she agrees that it's better to keep them until there's a dire need and they'd solve it. He hopes that day will never come, which he thinks is probably rather selfish of him, but it's not like anyone goes around wishing for more dire needs to appear in their lives.
Theopho gave him his expensive custom headband, and a bag of silver and large chest of coppers besides, when he was freed, and he bought the second floor of a townhouse for gnomes within five blocks of the Bell of the Sea tavern, which is openly a meeting place for the free halflings of the city and widely, correctly, rumored to be a meeting place for the Bellflower Network as well. Tibex considers being part of the Bellflowers, but after he talks with the innkeeper of the Bell, decides that he would do better staying legitimate. He does scribal work for those who can't write, and when they need something made official, he puts on the enchanted armband in the shape of Erecura's holy symbol that he kept when he left Theopho's service and asks politely that a notary or official please approve these documents. This works better than you might expect at getting him treated almost like a tallfolk.
He's also been asked to intercede in disputes with tallfolk, twice, when his fellow halflings could tell they were being outright cheated and lied to but couldn't stand up to threats on their own. Not violent ones, there's not much he could do for that and Jamisa wouldn't permit it, but more subtle bullies. Again, he wears his armband and asks them politely what the trouble is, then provides the evidence that was already gathered. Again, this works better than you might expect. "That is unfortunate. I will have to ask the Watcher of the Runes if there is any other option to resolve this dispute." has proved shockingly powerful at convincing bureaucrats and burghers that they don't need to cheat these halflings quite so much after all. He hasn't even had to actually go and test his theory that Theopho would, in fact, stop giving advice to people who had offended his former slave.
They consider if they should try to elect one of their own, and Tibex asks Theopho about it, and is assured that no harm is going to come to whoever is elected. He relays it, and acquiesces to be their pick, but they ultimately decide that it's better to let the tallfolk bribe them; it doesn't seem likely anyone will listen much to halflings anyway. No one offers him a substantial bribe, and he ends up voting for Theopho.
He's almost put the convention out of his mind by the time Sarenith approaches. But then new free halflings start showing up in the city, with bright arcane marks showing that they're under the protection of the archmages who helped Her Majesty conquer Cheliax from Asmodeus. And so Tibex has some new work to do.