be the making of

be the making of somebody

if you say that an event or experience was the making of someone, you mean that it made them develop good qualities (never in present tenses) A spell in the army will be the making of him! University was the making of her, because she was able to escape the influence of her family at last.
See also: making, of

be the making of

Be the means or cause of progress or success, as in Marriage will be the making of him. This idiom, using making in the sense of "advancement," was first recorded about 1470.
See also: making, of
References in classic literature ?
To watch, teach, "form" little Flora would too evidently be the making of a happy and useful life.