What is an insurance bond? Can i bring the car into the country on a temporary permit and then try to sell once I'm in the country. Then pay the duty on it once I sell it?
I'm not aware of an insurance bond. Technically, when bringing a personally-owned vehicle into Belize you either pay the duty or get a temporary permanent with a deposit equal to the amount of the duty which is refunded when you leave the country. Sometimes the deposit is collected, sometimes it's not.
To be safe and perfectly legal: if you want to sell it in BZ, pay the duty and add it to the price.
You can get around all that with appropriate bribes to willing officials but it's just not worth the risk.