The question is oddly phrased. “She wants to be”, like going to the movies. Like a funny picnic. If she is a masochist/submissive, of course I would like her to live her life according to what she is and makes her feel good. Also, the question is asked as if it was a bad or lowly thing to be a masochist/submissive. Why would that be so? There are few lives that would be more perfect than being a masochist/submissive in a truly fulfilling relation (if one has that mindset). So, Yes.