She knew from a young age that her sole 'purpose' (in life) was to be a writer. [=she knew that all she wanted (in life) was to be a writer]
We were happy to know that the money was being used 'for a good purpose'. [=for something useful, important, etc.]
There's little/no 'purpose' in restarting the process. [=there is little/no reason to start the process again]
(..) to abandon the castle, you'll grant a safe passage north. You have my word. You have until nightfall. (sighs) You gave it to me for a purpose. I've achieved that purpose. It's yours. It will always be yours. One last thing, Ser Jaime. Yes, Lady Brienne? (..)2016 TvShow: Game of Thrones Title: No One Season: 6 Episode 8