WsopDK.. The guy who offered you $4000 for guide2poker is probably trying to fool you into ordering a domain appraisal. The same happened to me with youseek.info (I didn’t buy appraisal), and it has happened to lots of people. No-one in their right mind would pay that much money for guide2poker.info which is a very mediocre domain name.
If I were you I would order an appraisal for poker.fo and poker.gl instead..
Ps. The plot of the domain appraisal spammers is a bit complicated, I read about it but can’t remember it now.