Firm undertaking (6)
I believe the answer is:
pledge
(Other definitions for pledge that I've seen before include "Vow; security" , "Solemn undertaking" , "Give one's word" , "Plight" , "make toast" .)
I believe the answer is:
pledge
(Other definitions for pledge that I've seen before include "Vow; security" , "Solemn undertaking" , "Give one's word" , "Plight" , "make toast" .)