Just a look @ it!

Long back I have seen this first scene in a film. I remember it like this. A lttle girl and a
boy standing near to a lake ,it was night and there was thundering and lightening. The boy ask the girl "Can I kiss you? " She smiles and shows her cheecks. He kisses her. They watch the sky, ligtening and then the boy ask the girl "Will you marry me?" The girl asks "Why do you want to marry me?" And he says "So that I can kiss you without asking you whenever I feel like that". The answer appears to be cute.Indeed good considering it was a litle boy and a girl. :)
But Im thinking about the question "Why do you want to marry me?",seriously, and more seriously trying to find an answer for the question. Why do you want to marry anyone? 


Here is another scene. The couple is engaged. They sleep together.But the girl is a little confused. She asks the guy "Why do you want to marry me?" The guy replies , "Because I love you". This appears to be romantic , but Im not gonna buy this too.
A more practical answer would be We marry because we want to make some things certain. Like...You will be there for me when I need you, you will share with me "mine" and "urs', making it "ours", fun & joy & the pain and to have kids... and comfort me. And to make my life lovable, lively and beautiful till my end.
 Isnt this what we are looking in a marriage? I mean-a certainity in these things. 
 Cheers,
Tressy.