Make the first sentence usable
Lead with the reason for writing so the recipient does not have to decode a long emotional introduction. For a message about how to apologize for plagiarism in an assignment, use this factual base: name the assignment, rule, person, or shared work affected and do not conceal the extent of the problem.
Reduce the work of responding
Offer simple options, a narrow question, or a clear update that can be understood without another conversation. Ask which repair is permitted, complete your own work, and accept a fair academic consequence. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Respect the boundary already visible
Do not pressure a teacher or classmate to erase a consequence or support a false account. Report bullying, threats, abuse, and safeguarding concerns to a trusted adult or official school channel. A block, explicit refusal, legal restriction, or safety plan takes priority over the desire to explain more.