。
She had been yearning for love.
Literal
[topic-は] love [object-を] was-yearning-for.
切望 is a compound of 切 ('keenly, urgently') and 望 ('hope, wish, desire') — together it conveys an urgent, almost painful yearning, much stronger than ordinary 望む ('to wish') or 欲しがる ('to want'). It's literary in flavor and tends to appear in narrative or reflective contexts. The ~ていた form is the past progressive: not just 'yearned' (a single moment) but 'had been yearning' (a sustained ongoing state in the past), suggesting this craving was a long-running condition.