confidential

adjective

1. Kept, or meant to be kept, secret within a certain circle of persons; not intended to be known publicly“The newspaper claims a leaked confidential report by the government admits to problems with corrupt MPs.”
2. Inclined to share confidences; (of things) making people inclined to share confidences; involving the sharing of confidences.“Sitting in front of the fire, they became quite confidential, and began to gossip.”
3. Having someone's confidence or trust; having a position requiring trust; worthy of being trusted with confidences.“a confidential agent; a confidential servant; a confidential whisper”