Instead of direct "no", say "how can I do that?" — opponent solves your problem.

Repeat the same refusal in the same words calmly, no matter how the other person reshapes the pressure.

Say no in three sentences: thanks, refusal, closing — with no "sorry" or justification.

Memorize one 7-word refusal sentence and rehearse it until it emerges automatically under pressure.

Don't ask AI "write in author X's style". That = using their commercial style sans permission.