First of all, we have no Idea if Crocodile would fall for her, secondly, Momomga inflicted pain on himself and managed to prevent getting turned into stone by doing so, therefore we have reason to believe a guy like Croc, who is infinitely smarter and should be at least aware of how Hancock's main abilitiy works, given his status, knowledge and connections and the fact he was present at Marineford, when Hancock used her abilities - should be able to draw the same conclusion.
However, assuming Croc would simply fall for her charme, that would still be an match up issue since her ability doesn't work in everyone by default.
You gotta judge Hancock based on her combat prowess, not just based on the ability to seduce men 😭
