Start with the part that is verifiable
Separate the event you can describe from the motive or reaction you are guessing. For a message about how to apologize for checking a phone without permission, use this factual base: name your behavior, its likely practical or emotional impact, and the agreement or trust it affected.
Make one answerable request
Give the recipient one concrete question or next step instead of several emotional jobs at once. 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.
Leave the recipient in control
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. A clear message remains useful even when the answer is no or no answer arrives.