。
She came to know the truth.
Literal
She [topic-は] facts [object-を] knowing [to-に] reached.
~に至る ('reach the point of, come to V') is a formal/literary pattern marking the culmination of a process. Built from 至る ('reach, arrive at, attain'), it suggests an extended journey or developmental arc that finally yields the marked result. Far weightier than the everyday ~ようになる ('come to V'). Common in essays, formal narrative, and legal/historical prose: 結論に至る ('reach a conclusion'), 完成に至る ('reach completion'). Here 事実を知るに至った frames 'finding out the truth' as the endpoint of a longer arc.