Start her by telling her you love a girl X. Out of curiosity, she will start listening
Tell all the beautiful things about X
All sweet things made by X which made you happy
How you fell in love with X
What are all qualities which make X an angel
What all you will do to make X feel like a princess
On how serious you are about growing up with X
On what X means to you and how X creates an impact on your life
After this you will realise that your girl is actually loving it or enjoying it. And at that time, go down on one knee, hold her hand and tell her that she is that X and that she means the world to you and you will do anything to make her feel like a princess.
There you go man! You won the girl’s heart.
Better you do it in a crowded place. People will go aww over you and appreciate your awesome sense of love. And this will make her go double aww.