Nouns ending in -ence are usually feminine.
The suffix forms abstract nouns, often from verbs.
Is innocence masculine or feminine?
l'innocence
The rule behind it
97.6% of -ence nouns are feminine
In context
Je peux facilement vous convaincre de son innocence.
I can easily convince you of his innocence.
Tu ne dois pas profiter de son innocence.
You must not take advantage of her innocence.
La preuve nous a convaincus de son innocence.
The evidence convinced us of his innocence.