。
She was forced to confess.
Literal
She [topic-は] forcibly was-made-to-confess.
無理矢理白状させられた — 無理矢理 (むりやり, 'forcibly, by force') is a strong adverb. 白状させられた is the causative-passive of 白状する ('to confess'): 'was made to confess.' The causative-passive stacks both being compelled and being the subject of that compulsion.