Name what the advertisement is doing
Use a concrete observation: “That clip is trying to make us interested in the movie.” Ask which part looked appealing. Your child may want to see a funny creature, hear a song, or join a conversation friends are having. Understanding that interest helps you respond to the request itself. Avoid treating enthusiasm as evidence that the child has been fooled; adults can enjoy advertising too while still choosing how much weight to give it.
Review the complete decision
Check the film rather than relying on a trailer’s tone. Then separate the cost of watching from extras such as special seating, themed snacks, or toys. If the outing does not fit the budget or schedule, say which part is unavailable and what alternatives exist. Do not promise a later streaming release date or price unless you have verified it. A plan to reconsider when the film is available through your existing access is different from a guarantee that it will arrive soon.
Keep the answer specific
You might approve the film but decline merchandise, or choose a home viewing instead of a theater visit. Explain those as separate decisions so the child understands what the yes covers. If the answer is no for now, offer a date or condition for revisiting only when you intend to follow through. The conversation can help the family distinguish wanting an experience from needing every item associated with its campaign, without shaming the child for being excited.