The first thing that you need to do before persuading your mom for love marriage is to talk to the girl one final time in order to ensure that she really is willing to get married to you and is already ready to meet your mom.
Invite or bring your girl over to your house in order to introduce her to your mom in case she is a stranger. Be sure to give a proper and complete introduction, telling you mom exactly who she is, how you met her, what she does, etc. If she is an old friend that you mom has already met, then have her come over for lunch or dinner so that she is there to help you persuade your mom about letting you get married to her.
Tell your mom why you love the girl and why you want to get married to her. Be honest about your feelings since it is your mom you are talking to and she deserves to know the truth about your feelings. You should also allow your girl to talk to your mom while the discussion is active, so that she can support your point of view. She might add something to your point of view that would get your mother persuaded.
Leave your girl alone with your mother for a while so that they can talk to each other more frankly. Both your girl and mother may be reluctant to talk freely in front of you, which is why you should leave them alone for a while.
After the girl leaves, sit down with your mother and ask her how she feels about the girl. Patiently listen to what she says. If you do not agree with your mom’s point of view, do not interrupt rudely. Wait for your turn to speak and then express your own views.
Your mother may ask you more questions now that she has met the girl. Answer them honestly.