Is it ensure, insure, or assure?
"made of salt," c.1500, probably from a Latin word related to salinum "salt cellar" and salinae "salt pits," from sal (genitive salis) "salt" (see salt (n.)). Also in Middle English as a noun meaning "salt pit" (13c.). Saline solution attested from 1833.
saline sa·line (sā'lēn', -līn')
Of, relating to, or containing salt; salty.
Of or relating to chemical salts.
A salt of magnesium or of the alkalis, used in medicine as a cathartic.
A saline solution, especially one that is isotonic to blood.