This central American country has long been a favorite of American and British retirees. A former British colony, the national language is English, and the infrastructure and services are relatively modern and up to date.
Here’s the Belize government’s portal. The immigration information here is contained in pdfs, and not well organized.
Here’s the advice of the American embassy in Belmopan on emigrating to Belize, which looks relatively easy compared to many other countries.
Here’s a quick guide to living in Belize, focused on retirees.