Is it ensure, insure, or assure?
also doozie, 1903 (adj.), 1916 (n.), perhaps an alteration of daisy, or from popular Italian actress Eleonora Duse (1859-1924). In either case, reinforced by Duesenberg, the expensive, classy make of automobile from the 1920s-30s.
A person or thing that is remarkable, wonderful, superior, etc; beaut, humdinger: a little 30-page doozey called ''Making Chicken Soup''/ Want a swell Naval Air Station? I got two doozies up for grabs
[1916+; origin uncertain; perhaps fr a humorous repronunciation of daisy; certainly reinforced by dusy, duesie, and other shortenings of Duesenberg, the name of a very expensive and desirable car of the 1920s and '30s]