Zoro realized everything she said was true. He was uncomfortable around her being so nice and forward with her feelings because down inside him, he still felt like she was just using him for her own gain. He felt stupid, mostly because even after Robin's cry, he still thought she would just use him and throw him away when she got to bored. No matter how scary looking or intimidating he looked, Zoro was still gullible and nice to people in need. He was like Luffy that way, the only reason people wouldn't think he and his captain had same ideals and personalities was because Luffy acted stupid and goofy, while Zoro was headstrong and serious. But overall, Zoro was still at a more emotional disadvantage than others. That's why he was the quite one, only speaking once he had thought through the situation enough. Like the time with Usopp quitting and the crew wanted him back. With Robin so up front and wanting his feelings to return to her what she felt for him, Zoro just didn't know what to do.
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxx
That night Zoro went looking for Robin, he had thought all day of what to say to her, and he finally knew what it would be. Though, he could not find her any were.
Little did he know, Robin had gotten drunk earlier in the day and was mopping over him all day. Nami had tried to comfort her but to no avail. While Zoro was looking for her, the still very much drunk woman knocked on a door. "Who is it?" a man asked, "Sanji-san, it's me, Robin." Sanji quickly opened his cabin door. "Robin-chawn? What are you doing here?" Robin looked drunk as well as horny, "C-can I come in... cook-san?" see sounded vulnerable and seductive.