She was unmoved even by her husband's death.

Literal

She [topic-は] husband's death [at-にあっても] heart [object-を] was-not-moved.

にあっても means 'even when confronted with' — a formal expression. 心を動かされなかった is the negative passive of 動かす, meaning 'her heart was not moved.' The implication is striking emotional coldness.