Yeas ago I was selling a truck. The buyer said "ok I'll pay your asking price if I have 7 days buyers remorse if I take to a shop and it's costly to fix" and I replied with "must have less than 200KM on it and be in the exact same condition, no dents, no damage at all and we can document everything now and sign it and make a copy for both". I never did see that truck again...