。
She achieved great success in her own business.
Literal
She [topic-は] her own business [in-で] great success [object-を] obtained.
成功を収める is a stock collocation meaning 'to achieve success' — 収める here doesn't carry its literal sense of 'to put away / store' but the figurative 'to attain, reap.' The pairing of the formal na-adjective 偉大な ('great, magnificent') with 事業 ('enterprise, undertaking') and the ~を収める idiom gives the line a written, almost biographical register, even though the verb ending is just plain past 収めた.