From English - German Ding/FreeDict dictionary ver. 1.9-fd1:
insure /ɪnʃˈʊə/ <v>
[Am.] etw. gewährleisten, sicherstellen, sichern, für etw. sorgen <v>
Synonyms: ensure, assure, guarantee sth.
see: ensuring, insuring, assuring, guaranteing, ensured, insured, assured, guaranteed, ensures, insures, assures, guarantees, ensured, insured, assured, guaranteed, This is the only way to guarantee that …