Is it ensure, insure, or assure?
Old English husbonda "male head of a household," probably from Old Norse husbondi "master of the house," from hus "house" (see house (n.)) + bondi "householder, dweller, freeholder, peasant," from buandi, present participle of bua "to dwell" (see bower). Beginning late 13c., replaced Old English wer as "married man," companion of wif, a sad loss for English poetry. Slang shortening hubby first attested 1680s.
"manage thriftily," early 15c., from husband (n.) in an obsolete sense of "steward" (mid-15c.). Related: Husbanded; husbanding.
i.e., the "house-band," connecting and keeping together the whole family. A man when betrothed was esteemed from that time a husband (Matt. 1:16, 20; Luke 2:5). A recently married man was exempt from going to war for "one year" (Deut. 20:7; 24:5).