Is it ensure, insure, or assure?
Old English *snyflan "to run at the nose" (cf. snyflung "running of the nose"), related to snofl "nasal mucus;" see snout. Meaning "to be in an (affected) tearful state" is from 1680s. Related: Snivelled; snivelling. As a noun from 14c. Melville coined snivelization (1849). Middle English had contemptuous term snivelard (n.).