Yeah, she really believes she has a half-brother, so that would be seen as "true" to the faceless men, who use FBI type physionomy analysis or whatever it's called, pupil dilation and breathing and shit like that. They don't have any magical ability to determine truth and lie, as far as I know, it's all training.
At the Tower of Joy I kinda expected the king's guard to say "Woe to the Usurper if we had been" in response to Stark asking about their absence from the Trident, but they modernized it to "Good for him we weren't" or something along those lines. Woe is such a ponderous, dramatic word, I didn't even realize I remembered that line from the books until I noticed it's absence. And the swamp guy Reed is the one that saves Stark, as was hinted at in Ned's internal dialogue in the first book. Kinda expected it to be by poisoned arrow though, but backstabbing drives the point that he isn't some pamby knight concerned with honour well enough.