en·sure 
/ɪnˈʃuɚ/ verb
en·sures; en·sured; en·sur·ing /ɪnˈʃuɚ/ verb [+ obj] : to make (something) sure, certain, or safe
▪ They took steps to ensure the safety of the passengers. ▪ We want to ensure [=make certain/sure] that it doesn't happen again.
▪ They took steps to ensure the safety of the passengers. ▪ We want to ensure [=make certain/sure] that it doesn't happen again.
