Ok..didnt both of u know from the begining tht both of u belong to a bit different caste? Why didnt the girl tell u in the very begining tht her parents would object to your caste, before proceeding ahead in an affair? She should have known this already then....
Ok..now as some ppl are suggesting tht she might have lost interest in you, thts why she might be avoiding u..its very much a possibility..u should think abt it seriously.....but only u can judge her better..
If u think, she is genuinely involved in you, then what u must do, is , first convince your own parents, and then ur parents must take ur proposal to her house, as a neutral party... Theres no need to show, tht both of u are involved in each other..or even know each other...Maybe ur parents can say something like we saw her in some wedding party..or whatever..take the proposal, as in arrange marriage cases...once ur propsal is there, then maybe she can confide in her sister(if she has)or through some friend, she can try to convince her parents....try your luck once... If not successful, then this must be better for you....but i am still unable to understand why didnt she tell u abt the caste problem, in the very begining tht her parents woulnt agree to this...