One Piece S04E72 - Say You Want to Live! We are Friends!!

Robin finishes her story and says that while she considers the Straw Hats her friends, she believes that one day, they will be no longer able to protect her from her pursuers, and betray her like the others did. After Spandam points out that taking in Robin means declaring war on the entire world, Luffy tells Sogeking to shoot the World Government flag. Sogeking uses his Sure-kill Firebird Star to burn up the flag, declaring war on the world for Robin's sake. Robin, moved by the depth of Luffy's action, cries out that she wants to live and return to the sea with Luffy, and Luffy and the others prepare to do battle with CP9 and save Robin.