。
She turned down our offer of help.
Literal
She [topic-は] our help [of-の] offer [object-を] refused.
Two derived nouns stack to form the object phrase: 援助 ('aid, help' — a Sino-Japanese compound) and 申し出 ('offer, proposal' — a verbal noun derived from the masu-stem of 申し出る). The phrase 援助の申し出 ('offer of help') is then refused with 断る. 申し出 is one of many noun-form compounds (申し込み 'application,' 引き出し 'drawer,' 払い戻し 'refund') built by joining a verb pair and using the masu-stem nominally — a hugely productive pattern in Japanese vocabulary.