Is it ensure, insure, or assure?
Jacobi Ja·co·bi (jə-kō'bē), Abraham. 1830-1919.
German-born American physician who established a children's clinic in New York (1860) and is considered the founder of American pediatrics. His wife, Mary Corinna Putnam Jacobi (1842-1906), also a physician, helped expand opportunities for women in medical education.