Is it ensure, insure, or assure?
seta se·ta (sē'tə)
n. pl. se·tae (-tē)
A stiff hair, bristle, or bristlelike process or part.
Plural setae (sē'tē)
A stiff hair, bristle, or bristlelike process or part on an organism. Setae on the bodies of spiders are used as sensory organs, while setae on the bodies of many polychaete worms, such as earthworms, are used for locomotion. Microscopic setae on the feet of geckos allow adhesion to vertical surfaces.