So sorry for the late response!!
To get her second cg, after you have Sandrone's first event and after Pierrot says "I hope your day was enjoyable" You have to pick the option that talks about Rosaura.
Continue the game as normal until Pierrot asks you if you want to go back to the apartment with him, you have to say no and take a walk on your own.
There game should remember your answer and start a special event with Rosaura.