、。
Her curiosity got the better of her, so she opened the box.
Literal
She [topic-は] curiosity [subject-が] strong-was [because-ので], that box [object-を] tried-opening.
好奇心 ('curiosity') is built from 好 ('like') + 奇 ('strange, unusual') + 心 ('heart, mind') — literally 'a heart that likes the unusual.' 好奇心が強い ('curiosity is strong') is the standard collocation for a curious nature. ~てみる ('try to do, do and see') is the auxiliary of attempting and discovering; 開けてみた means 'opened it (to see).' The Pandora's box motif is universal — opening what one shouldn't out of curiosity sits at the heart of many myths, including the Japanese tale of 玉手箱 (the hidden-treasure box) in 浦島太郎.