Who is Katrina Leroux/Courtney from When the Lion Feeds and what is their importance?

Katrina is a soft spoken, and simple country girl that Sean finds traveling with her family in the bush veld. She is slim and elegant for her age, and she marries Sean at the tender age of sixteen, but Ouma Leroux has coached her well. She can ride, cook, clean, cut hair and she is beautiful and untarnished as well. Coming from a small family, she has been relatively sheltered all of her life. She is vulnerable, easily embarrassed and innocent to the core. When she accepts Sean as a husband, they are deep in the bushveld, and Sean swears on the family's Bible that he will look after her for the rest of his life.