Both when dating and when buying used cars, I require an intermediary to introduce me, as otherwise I am not willing to trust in the owner/person directly. My safety is paramount and requiring a 'middleman' drastically reduces the chances of malicious behavior by the owner/person.

Clearly there is, as people like to buy certified pre owned used cars and meet people via acquaintances.

Perhaps some people don’t have the time or ability to evaluate a used car, or a life partner. Or they feel the broker reduces risk as they might offer some guarantee of the product.