"装成规矩的女人" can be translated into English as "pretend to be a well-behaved/proper woman" or "act like a conforming/conventional woman".
Here are some nuanced variations depending on the context:
"pretend to be a well-behaved woman" (emphasizes the act of feigning good behavior)
"act like a conforming woman" (highlights adhering to societal norms)
"pose as a proper lady" (more formal, with a touch of old-fashioned charm)
Choose the phrase that best fits the tone and situation of your communication.