When it sells: marking it, and what stays on the record
Mark the listing sold the day the money lands, not the day someone promises. A listing left live after the vehicle is gone earns you calls you have to apologise for, and it is the commonest reason a seller stops answering the phone at all.
You can put the price it actually sold for. It is not shown to buyers as your asking price was; it goes into the record that makes the next seller's Worth today figure a little truer. A market only knows what it closed at if the people who closed say so.
The listing itself stays in your account after the sale, with its photographs and its dates. Withdrawn is the other ending, for a vehicle you decided to keep; it is not a failure and it carries no mark.