Name the impact without exaggerating it
Describe who had to wait, worry, redo work, spend money, or make a choice with incomplete information. For a message about how to arrange return of a family heirloom, use this factual base: list the specific item, ownership, condition, current location, and any real deadline.
Make repair practical
Offer the repair you can actually complete, with ownership, timing, and any limit stated honestly. Offer a neutral handoff, tracked delivery, or authorized third party and confirm when the matter is closed. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Let future behavior carry the proof
Do not enter property, withhold unrelated items, attach emotional conditions, or arrive without agreement. Use a public place, third party, workplace process, or legal support when ownership or personal safety is disputed. A promise inside a message is weaker than a visible change in what you do after it.