。
She wouldn't go out of her way to do something so foolish.
Literal
[topic-は] going-out-of-her-way such foolish thing [contrast-は] not-do.
わざわざ is a mimetic-flavored adverb meaning 'go out of one's way to' — it implies that the action would require special effort or detour, often carrying a tone of unnecessariness or sarcasm. Compare わざと ('deliberately, on purpose') — they look similar but differ: わざと emphasizes intent, わざわざ emphasizes the gratuitous effort involved. The contrastive は after ことは (rather than just を) adds emphasis: 'such a foolish thing — that, she wouldn't do.' The negation thus targets specifically that category of action.