。
She has a strong personality.
Literal
She [topic-は] individuality [subject-が] strong.
A textbook XはYが pattern: the topic 彼女は ('as for her') frames the discussion, and 個性が強い ('individuality is strong') supplies the comment about her. This 'topic + inner-attribute' frame is one of Japanese's most useful: 象は鼻が長い ('elephants — noses are long'), 私は頭が痛い ('me — head hurts'), and so on. 個性が強い carries a slight warning edge — closer to 'has a forceful personality, is strong-willed' than purely complimentary 個性的.