someone's word is their bond
(one's) word is (one's) bond
One always keeps one's promises. I promise that I'll be there in time with the money for the deposit: my word is my bond.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
someone's word is their bondsomeone keeps their promises.
A variant of this expression, now rather dated, is an Englishman's word is his bond .
Farlex Partner Idioms Dictionary © Farlex 2017