I am an educated hard working guy. I have a girlfriend and we are in relation from 4 yrs. Now we want to marry but girl's father is not agree in any cost and he forces to marry her with another guy. Now a days she is delaying it but I must do something now. His father is reputed and from higher society than me. How to I express myself opposite to him. Please help me.

Why don't you ask your girl to ask her father about the reasons for which is not allowing you both to marry ? First you should know all reasons, only then you can work on it. Btw, since its about girl's father, you can't do much without her help.