。
She worked hard to finish the job.
Literal
She [topic-は] that work [object-を] cause-to-end [intent-と] well worked.
終わらせる is the causative of 終わる ('end, finish' [intransitive]) — 'cause to end, finish [transitively].' ~ようとする ('try to do, intend to do') frames this as effort directed at the goal. The full structure ~ようと + [verb] uses ようと as a conjunctive form: 'aiming to [X], [Y].' 良く ('well, much') is the adverbial form of 良い, here intensifying 働いた ('worked'). Together: she tried to finish, working hard at it.