This may sound unpleasant to you but if you were knowing that your parents are not going to approve such relationship you should have informed them about your liking and getting close. Probably you might have ignored their approval or taken them for granted. Now you do not want to loose them! I think, now you need to wait until he gets job because no one would like to marry their daughter to jobless person unless he is doing higher studies which assures bright future prospects. Mean while you can open discussions about love, marriage, caste etc in general so when you talk about him they will be already knowing your ideology.