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]
(..) Legendary warrior, everyone said. Have you done much fighting yourself, Lord Frey? I'm a bit old for all that. No, but back in your day. The purpose of fighting is defeating your enemies, isn't it? I've defeated mine. Riverrun belonged to House Tully for a thousand years. Now it's mine. (..)2016 TvShow: Game of Thrones Title: The Winds of Winter Season: 6 Episode 10