Is it enough to just verbally ask a buyer to keep things confidential?

It offers some protection, but it's considerably weaker than a written agreement, and not something to rely on for anything genuinely sensitive. A verbal request can still support an argument that information was shared in confidence, but proving exactly what was said, what it covered, how long it was meant to last, and that the other side actually understood and agreed to it becomes a matter of competing recollections rather than a clear document both sides signed.

A written confidentiality agreement solves this by fixing the terms in advance: what counts as confidential, permitted uses, duration, and what happens if it's breached, all agreed before anything sensitive is shared. This removes the ambiguity a verbal request leaves open and gives you something concrete to point to, and to enforce, if things go wrong. For anything beyond a casual, low-stakes conversation — financial details, customer information, or anything that would meaningfully hurt you if disclosed — a signed agreement is worth the modest effort before you talk further. A Treadstone business lawyer can provide a standard NDA you can use consistently rather than relying on verbal requests case by case.