"What's your dream?"
Every member of the crew wanted to accomplish something. Everyone that is, but her.
Days, weeks, and now months had passed since she'd first been asked that question, and she still didn't have an answer. Before Luffy had asked her that she had never even thought about 'dreams' or goals for the unforeseen future. All she ever did was fight to survive long enough to see another day.
She was now an official member of the Straw Hat pirate crew, but she still didn't have an answer to her Captain's question.
Just what was it that she wanted? Well, that was simple enough: she wanted to survive.
For what reason did she want to live so badly? For that however... she didn't have an answer. She just wanted to continue existing, that was all, and yet... it was nothing. It was absolutely nothing because in the end she had no purpose, no dreams or goals of her own.
Why then, had she fought so hard to see another sunrise for all these years? What was her purpose? What did she want out of life?
... She just didn't know.