Write from facts rather than momentum
Pause long enough to remove accusations, assumptions, and details that belong to someone else. For a message about how to decline a funeral invitation respectfully, use this factual base: acknowledge what was requested, any real timing issue, and whether your answer applies only now or more broadly.
Offer a proportionate next step
Match the size of the request to the relationship and to what the recipient can reasonably decide now. Give a direct no, a limited alternative only if you mean it, and any practical information they still need. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Protect privacy on both sides
Do not overexplain private details, blame another person, or say maybe when the answer is no. When pressure, coercion, or retaliation is possible, use a safer channel and involve appropriate support. Use the most private legitimate channel available and do not share the exchange to recruit support or pressure.