。
She's convinced of my innocence.
Literal
She [topic-は] my innocence [object-を] is-convinced [explanatory-んだ].
潔白 ('innocence/integrity') and 確信する ('to be convinced') are both Sino-Japanese compounds. The sentence-final んだ adds an explanatory tone, as if the speaker is conveying this as a noteworthy fact to reassure someone.