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]
(..) (CHUCKLES) I will try. As I'll also try to be worthy of you, Judith. To everything there is a season, and a time for every purpose under the sun. A time to love, and a time to hate. A time of war, and a time of peace. Now this is the time of war! This is the time to hate! (BREATHING HEAVILY) (..)2017 TvShow: Vikings Title: On the Eve Season: 4 Episode 19