Complex sentence: Early in her life she read an autobiography of the French Saint Thérèse de Lisieux; the experience had a profound effect on her already pious persona, coming to the realization she wanted to serve God.
Split into simpler sentences: Early in her life she read an autobiography of the French Saint Thérèse de Lisieux. The experience had a profound effect on her already pious persona, coming to the realization she wanted to serve God.