Dear Mr. Jagdish,
I am overjoyed to hear of your engagement of Miss Usha.
Miss Usha had always been a brilliant and intelligent student in the college, besides being beautiful, vivacious and cultured. While you are lucky in getting such a nice life companion, I must say that she too is equally lucky in getting a handsome, bright and cultivated young man like you for her husband.
Please accept my heartiest congratulations on this happy occasion. I look forward for the happier occasion, your wedding.
Wish best wishes and good luck.
Yours sincerely,
Name