。
She blushed.
Literal
She [topic-は] face [object-を] reddened.
顔を赤らめる ('to redden one's face') is the standard literary expression for blushing. 赤らめる is the transitive verb derived from the intransitive 赤らむ ('to redden') — the productive ~める suffix turns intransitive verbs into transitives (集まる→集める, 緩む→緩める). Framing the blush this way makes the subject grammatically responsible for it, giving the verb a more deliberate, novelistic feel than the everyday 顔が赤くなる ('one's face becomes red'). Either form can mean embarrassment, sudden affection, or modesty — context decides.