Answer:
an effusive manner of writing
first-person style of writing
an introspective frame of mind
Step-by-step explanation:
Effusive means expressing approval or pleasure in a way that shows very strong feeling; introspective means examining and considering one's own ideas, thoughts, and feelings.
The very beginning of Confessions shows the above-mentioned characteristics:
"I have entered upon a performance which is without example, whose accomplishment will have no imitator. I mean to present my fellow-mortals with a man in all the integrity of nature; and this man shall be myself."