Rebuild the missing context
Assume the recipient will not remember every date, promise, or earlier conversation. For a message about how to apologize for criticizing a partner's appearance, use this factual base: name your behavior, its likely practical or emotional impact, and the agreement or trust it affected.
Say what needs to happen next
State the decision, information, or practical action you need and include a real deadline only when one exists. Offer a specific change the other person can observe and ask what repair would actually help. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Avoid making urgency into pressure
Do not explain away the behavior, bargain for affection, or use gifts to skip accountability. Respect separation, no-contact, and safety plans, and use professional support when coercion or abuse is present. Do not make the other person responsible for reducing the discomfort that prompted you to write.