When someone emails to ask, “would you sell X for $xx,xxx?” I look at as a fishing expedition. Some may also call it tire kicking, but people who ask about buying a domain name at a certain price are usually more interested in fishing for the right number rather than simply kicking the tires on a domain name. I know this because I sometimes do it when I am trying to buy a domain name.
Asking “would you sell…” is non-committal. If the domain registrant replies affirmatively, the person who inquired can say something like “I will get back to you.” This is contrasted with a direct offer that is something like “I would like to offer you $xx,xxx to buy X.” If the domain registrant agrees, that is pretty much like a handshake deal from my perspective.