。
She raised two children.
Literal
She [topic-は] two-people's child [object-を] raised.
二人の子 uses the counter-modifier construction: counter + の + noun = 'two children.' Compare 子供を二人 ('two children' as a quantity-adverbial after を). 育てる is the transitive 'raise' (kids, plants); the intransitive pair is 育つ ('grow up').