How to solve my marry problem to my rakhi sister

i love a girl but she tied me rakhi before 6 year in school.at that time i love her but i don't told her because of i scare she leave me.after some year i told her about my feeling.there have no problem between us.our family know about both relation as rakhi brother sister after finish school she tied me rakhi at her home last 3 year.we are share everything about us life and we are like good friends.as we are close and as we growth then realize we are in love and there have a mistake.both are love each other but how to convince family.she is scare and after 2 year break our relation and end all communication with me.we more close to each other we have also physically it is wrong but i try to solve it and she say me forget it .but i not forget it.so please help me to sole it.what i do and what is wrong and right.help me about it .anybody who have same problem and solve it please help me .it is my life. please friends.

Tying the rakhi as brother and sister means your families except you as friends only and not as boyfriend and girlfriend? What is the custom in your religion that would have the families accept you as her boyfriend?

i don't know about it.but i try to convince and we also different cast and Hindu religion.i not live without her.i want to opinion of people what is wrong and right.i jut try to solve this problem.any people face this problem and solve it so plz help me.