late 14c., of persons, "confident, self-assured," past-participle adjective from assure. From early 15c. as "secure, made safe." Related: Assuredly; assuredness.
Entries linking to assured
assure v.
late 14c., "reassure, give confidence to; make secure or safe, protect; bind by a pledge, give a promise or pledge (to do something)," from Old French asseurer "to reassure, calm, protect, to render sure" (12c., Modern French assurer), from Vulgar Latin *assecurar, from assimilated form of Latin ad "to" (see ad-) + securus "safe, secure" (see secure (adj.)). Related: Assured; assuring.
self-assured adj.
"self-confident, feeling confident and assured as to oneself," 1711, from self- + assured.