What is the author's tone in Mother Teresa, in My Own Words by Mother Teresa?

The tone of Mother Teresa: In My Own Words is that of a deeply committed Christian nun and humanitarian with an extremely strong series of value commitments. Teresa is absolutely convinced that Christianity is true and that God has called her to serve the poorest of the poor. For this reason, she often speaks with a sense of calm certainty and profundity about her mission and experiences. Her tone is also very loving, containing many expressions of pleasure at seeing love in others and being able to help the sick and the dying.