confirm (v.) Look up confirm at Dictionary.com
mid-13c., confirmyn "to ratify," from Old French confermer (13c., Modern French confirmer) "strengthen, establish, consolidate; affirm by proof or evidence; anoint (a king)," from Latin confirmare "make firm, strengthen, establish," from com-, intensive prefix (see com-), + firmare "to strengthen," from firmus "strong, steadfast" (see firm (adj.)). Related: Confirmative; confirmatory.