be the making of (someone or something)
To be the event or occurrence that leads to sustained success or a desired level of achievement. This big promotion could really be the making of Caroline's career. This meeting could be the making of me, so I can't miss it for anything.
be the making of someone/something
If something is the making of a person or thing, it is the reason that they become successful or become very much better than they used to be. The school seemed so far away from home, but it proved to be the making of me. Arguably, the motorway has been the making of modern Cambridgeshire.