Yumiko was not weak, she knew what she wanted and what she felt, she didn't hide her feelings nor did she try to be sneaky with them; she was awful at keeping secrets and an enabler to the Great Captain Usopp and all of his lies. Zoro didn't care; he still loved her. She didn't care about his faults either, she refused to deny her love for him. It's a shame that her love barely had a chance to be felt by the swordsman before it was taken away from him.