Help me in this situation.....?

She might be in relationship with someone already and may be she does not want to share this with anybody. Basically South Indian girls are not open to let other ppl know about their love life and mostly it goes as a preserved personal secret. And I can understand only this from what you have mentioned. May be you should try becoming a good friend of hers wherein she can confide to share her personal things with you... Good Luck!