Being Forced for Registry marraige by a female colleague

I am being forced by a female colleague for registry marraige. I never wanted to marry her & neither want to be with her. Now she threatens to go police & file case on me. Backdrop:- I started speaking to her with no intentions to get close or marry or getting physical. But with time and circumstances we had physical relationship, I clearly told that time I do not want to get married, She told its okey neither she wants.After sometime I started refusing. But she kept coming, kept knocking on my doors at night and most of the time threatened to shout & go to police to complain that I have shown the address of my room. So It continued. As I stay alone and both of us kept it a secret, I did not discuss anything about this to anyone (which has become my greatest fault). Some weeks back she got pregnant and she asked me to registry. I declined and told her I never wanted this & neither she did (on pregnancy). She aborted. Now she asks for Registry. What are my options?