Her success is 'just reward for' her hard work. [=she deserves her success because of her hard work]
She is 'reaping the rewards' of success. [=is getting all the good things that come with success]
The police are offering a 'reward for' information leading to the capture of the fugitive.
(..) themselves in courage, and proved themselves worthy successors to the armies of Charlemagne. You are the savior of Paris. Tell me, what can I give you as a reward? It distresses me to say so, your Highness, but I fear the trust you have placed in the Northman Rollo is misplaced. (..)2016 TvShow: Vikings Title: Portage Season: 4 Episode 8