。
She was so distressed that she shed tears.
Literal
She [topic-は] painful-was [because-て] tears [object-を] flowed.
つらい (i-adj, 'painful, distressing, hard to bear') is the standard word for emotional pain or hardship — distinct from 痛い (physical pain) and 悲しい (sad). The te-form つらくて gives the cause: 'because (it/she) was so distressed.' 涙を流す is the standard idiom for crying — literally 'let tears flow,' more formal/literary than the everyday 泣く ('cry'). The combination puts the reader inside a quiet, private grief.