How to convince my girlfriend's mom and dad for marriage?

It depends on your guys' ages. If you two are under 18, then there isn't anything you can do. But if you two are 18 or over, then her parents can't tell her who she can and can't marry. You should mention it to them, but obviously not in a rude way. Try sitting them down and saying "I really love your daughter and we are of age, so I was hoping you guys would let me take her hand in marriage. I will treat her the way she deserves to be treated, I will take care of her, and fufill my duties as a husband". Marriage can sometimes be hard for parents to accept, it's hard seeing your little girl grow up.

Well you two are going to be spending the rest of your lives together. Would they rather her marry a guy who she barely knows and be unhappy for the rest of her life and always thinking "what if..?" Parents always look to their pride and respect. If her parents say ok, and if society and relatives know that her parents are not against the union, then they will not loose respect. Some people will always be stubborn and people will always say mean things, no matter what you do, just to make themselves feel and look better to society. But if they have it in their heart to say mean things, then they are not true friends of her family. If her parents have been living good and honest lives, then in the minds of worthy and intelligent people, they will not loose respect. First ask them how they will loose people's respect, and what will people do to them is they lost their respect. In the end, when a person is on their deathbed, they will not think about how this girl and that guy had an intercaste marriage, they will think about their own life, and whether they think they lived their life well. THey will not think about how you and your gf lived your lives. Second, tell them that this will give them an opportunity to find out who their true friends are. Which relatives and friends will be there for them when times get rough. True friends and true relatives do not abandon you, for something their kids did. Third, show them how much worse it can be. At least you have the same culture, religion (?), language (?)..etc Fourth, tell them that you will be there for them when no one else will. When it comes down to it, in this world, people only care about themselves, and only look out for their best interest. Tell them that you will be here for them, when everyone else is too busy with their lives (and MEAN IT, be sincere).

When you know their prejudice against you why do you love her so much, only to enjoy illegal sexual pleasure ? Or you want to say that you are perfect for her but you don't know the tact of talking to break their prejudice, bias, apprehension, confusion against you; melt them, convince & reverse them to your favour making you much easier marrying her ? For that you must ask her how you practice talking to them very sweetly, simply & politely such that you get an opportunity of talking to her parents fully & convincing too because she only knows their behaviour best.

Why they are against you? You belong to different caste? You earn less than her? You come from poorer section of society?

If she is financially independent and she is ready, go to a court and get married. her parents will either accept you or kill her if she is from north India. Both ends well.

You don't need her parent's permission. She is an adult, she can do whatever she wants.

think why they r not agreed and work on that.

you should say why ..