NO. Followed by a puzzled look and a little pushback.
Sometimes there is more to this NO than I can Explain.
Sometimes there is no time to give the explanation due to the circumstances.
Sometimes there are others around who cannot hear the details.
NO needs Trust.
Trust that when the awkward No arrives and seems out of context that there is something more at stake.
Trust that when the situation calms or the opportunity arises, the explanation will come.
Trust that trusts you.