。
She didn't even need to do that work.
Literal
She [topic-は] that work [object-を] do necessity [topic-は] not-was-past [regretful-のに].
~のに at the end of a sentence carries a wistful, regretful, or reproachful tone — 'and yet, despite that, although [it was unnecessary].' The trailing のに is a discourse marker that leaves the sentence emotionally hanging, with the listener meant to fill in the implied contrast: 'she didn't need to, but she did anyway,' or 'she didn't need to, [what a shame].' する必要はない ('there is no need to do') is the standard expression for unnecessity; with ~のに at the end, it pivots from neutral statement to lament.