Want to do court marriage with GF, family emotionally blackmailing us

We are going to do court marriage but her family is against us & they are South Indians, I have threatened to life after marriage & also there is chance to emotionally blackmail her by her parents. I can't go to her area police station to do NC against her family because that area filled with South Indians & it will be dangerous to go there after marriage. 1. Can i do NC against her family in nearby police station of me & choose not to call her parents in police station to avoid blackmailing. 2. Can I ask my wife to give statement in written that she is marrying me with her will & not under any pressure (what kind of document it should be).