Breach of promise to marry

I was in love with a girl with whom I had worked in Chennai. So, I went to her home and talked to father. This happened about 2 years ago. Her dad didnt agree to marry her to me. From that place of work, I got a better job and I moved on to Banglore. My girlfriend got a job in Mumbai. In February 2013 I went to Mumbai and spent a night with her in a hotel room, I put a mangal sutra on her neck in the hotel room, but I didnt have sex with her. I put the mangal sutra just in case some police raid comes as she was afraid to stay. Next day morning, she went back to her apartment. Her relatives knew that she had spent a night with me, so, they sent her back to her home in Chennai. Her father told me that they are willing to marry her to me and asked my dad and me to come to her home and talk, but he refused to talk anything to my dad. Since, he never called my father and talked, we feared that it might be a trap to beat us up, so, we didnt go to her home. My parents told me not to keep contacts with her again. So, I kept all my phones off, and moved on. Later on, as father and myself didnt go to her home, she went back to her workplace in Mumbai. She started calling me, and I tried a lot to avoid her calls, but she was very persistent and finally I started talking to her again. About 6 months ago, I called her father, and talked to him. He spoke very rudely to me, and told me that he will never allow me to marry her and to keep out of her way. I told this to her, but still I couldnt stop talking to her. My parents found out this and in front of them I asked her, whether her parents would agree for the marriage, for which she said, they wont agree for our marriage. So, I cut the phone, and stopped taking calls from her. Now, I am about to get engaged to another girl, and my ex-girlfriend is threatening me through sms and emails that she will commit suicide and she will put a case against me. I tried a lot to avoid her, but she is very persistent and keeps me calling and sends me sms asking me to marry her else she will commit suicide. Neither me, nor my family is anymore interested in marrying her and I want to proceed with the engagement with another girl. I would like to know, what I should do in case if she puts a case of cheating against me on breach of promise to marry, what to do if she commits suicide saying I am responsible for her death. I believe I have done nothing wrong as I had spent night with her with her full consent, and I had talked to her father to marry her to me to which he didnt agree. Will I get arrested if she puts a case of cheating against me? I believe I had not done any cheating to her, as I was genuinely interested in marrying her, but, since her parents were not willing, I just moved on. Is it legally possible for her to put a case of cheating against me? How can I solve this problem. Please provide me your legal advice.