I am in love since last 2years but unfortunately I am love with my cousin sister who is my mamaji ‘s daughter and there was a positive response from her side. We both decide to marry but after some months, she started ignoring me. One day she told me to forget her but I am unable to forget her. What I should do? I could not understand is any thing wrong in that and what I suppose to do.

Hindu rituals do not allow such relations. . Even though if you want to try for this relationship, talk to her and find out the reasons of her back stepping.  If reasons does not sound logical to you then try to convince her through your logic. Please do not forget that it is her right to say no to the relationship. Do not pressurize her and accept her decision.