A remembered promise becomes real to a child long before fulfillment arrives.

Children do not hold a promise loosely. What an adult says in passing gets stored as something that has already happened, and the waiting that follows is spent inside that certainty rather than beside it. So a casual maybe can become a fixed plan in a small head, and the disappointment when it dissolves is not about the trip or the treat but about finding that words were less solid than they seemed.

Be slower to say yes than you need to be, and clearer about what is a plan and what is only a hope. If something you promised cannot happen, say so directly and early, and say why.