It’s not that Augustine immediately comes to affirm the catholic faith; rather, Ambrose’s kindness and hospitality to a precocious outsider was the affective condition for him to reconsider the faith he’d spurned. “I fell in love with him, as it were, not at first as a teacher of the truth—as I had no hope for that whatsoever in your church—but simply as a person who was kind to me.”
This is sort of like the story of Rumi and Shams. It is through one's experience with the beloved that one comes to know God. Deus caritas est.
