To bless or make holy; to treat or honor someone as a saint.
From be- (a prefix meaning to make or cause) combined with saint; this is an archaic or obsolete verb formation following Middle English patterns of creating verbs from nouns.
This word is basically dead in English, but it shows how productive the 'be-' prefix was in Middle English—you could slap it onto almost any noun to make it a verb, like 'befriend' did and still does.
Complete word intelligence in one call. Free tier — 50 lookups/day.