Can I sell a guold hall?

Is it possible to sell a guild hall>?

yes and what is a guold?

No, but it's possible to sell a Guild.

i think that is what he meant by guold hall

Exactly, you can't sell something that doesn't exist.

Ahh. so i cant sell the hall but I can sell the guild!?

Unless you want to take the risk of being scammed, there are no game mechanics to sell a Guild or Guild Hall.
If you trust someone very much, you can make someone else Guild Leader. That will take the Guild off your hands instantly, and you can ask money for it. That involves a whole lot of trust on both parties.

I am keen to sell my Guild... how much would one be worth do you think?

Free to a million.