as good as (one's) word
Reliable; truthful. Said of one who typically follows through on one's promises. Tom is as good as his word—if he promised to help you move, then he'll be here.
as good as one's word
obedient to one's promise; dependable in keeping one's promises. He was as good as his word. He lent me the books as he said he would. She said she would babysit and she was as good as her word.