If you've received an offer on MangoResort.com, then it must be from a resort -- present or future.
Resorts can afford a reasonable budget because they make good money from tourism and employ lots of people.
If there are no trademark issues AND if there are several existing resorts out there that have an equal stake in this name, then you should have no concerns about UDRPs or cease and desist letters. Not unless you ask for so much money that they become furious and try to circumvent a fair purchase.
It's a good name. And I think you'd be letting it go cheap at $2,500 if a resort is buying. Aim higher. Maybe as high as $15k. Beyond that is too "greedy" for my taste and might backfire. Stay flexible and be prepared to settle. Whether you get $8k or $3k, you can reinvest that money and make more than you can by holding onto this domain. Probably.