Why you can trust the answers
Because the model answers from the passages retrieved out of your own documents — not from whatever it picked up during training — the answers stay grounded in your material. It points back to the source, so anyone can check where an answer came from rather than taking it on faith. And because it's reading your documents at the moment you ask, not relying on having been trained on them, it works on material it has never seen before the instant you add it.
The model itself stays exactly as delivered: it does not learn from your data, it does not change between questions, and it does not drift as some outside vendor updates it.