i am in love.....how could i convince her that i love her so much????

Take a cue from that notorious romantic, Van Gogh.

She must see that you truly care about her feelings and how she views your relationship with her. She must be made to feel appreciated, understood, respected and loved. But a word of warning: even if you do all of this to the best of your ability there's no guarantee that she will choose you. Love is a funny thing...you can't MAKE someone love you, or make them love you the way you want to be loved.