Dear Mr. Smith,
Congratulations/Congrats on this big announcement! We are pleased to hear of your engagement news. Have you picked up the date for the upcoming nuptials? The company will offer you 3 days off, and if you need any help with the preparation, I can give you the name of the wedding planner. On behalf of the company, we wish you two a long and happy life together.
Sincerely,
Mary Chang