。
She's sentimental.
Literal
She [topic-は] emotion [to-に] fragile.
もろい (脆い) means 'fragile, brittle, easily broken.' When paired with 情に, it describes someone who is easily moved by feelings — sentimental, tenderhearted, quick to tears. The に marks what she's vulnerable to. This is generally a sympathetic description rather than a criticism.