suppose you have got a friend who wants to ge married.what would you tell him/her at his/her wedding night?I mean how would you congratulate him/her,What kind of sentences are common in such a case?
In the USA, we "congratulate" people when they get married. Congratulate means "you did a very good thing"...
"Congratulations, Tom, on your wedding. You will be very happy, I know. Debby! Congratulations! You found such a wonderful man.
My wife and I (or my family and I) wish you both all the happiness in the world. We are so happy for you. We are so happy that two such wonderful people found each other. I am sure you will be happy forever. I hope you two are as happy together as I am with my wife. Life was meant to be gone through two by two." (Two by two means two people walking together.)
And, if you want to joke with them, "Tom! I guess this is your last day of freedom! Poor man... you will never be free again! Debbie! Are you ready to be Tom's Boss for Life? Tom, I am so surprised, I thought you were going to marry that other girl you were kissing last week...."