Describing someone as sainted means they're almost unbelievably good and honorable. Everyone adored your sainted grandmother, who was kind to every single person she ever met.
You can use this adjective in a very literal way, to describe people who have been canonized as saints by the Catholic or Eastern Orthodox Church. The sainted figure of Mother Theresa is one example. But living people who are admired for being extremely virtuous can also be described this way: "My sainted English teacher is beloved by all her students."