How do you say be Happy Wedding day in Greek?

There isn't a single perfect translation for "Happy Wedding Day" in Greek that captures the nuance of the English phrase. The best option depends on the level of formality and your relationship with the couple. Here are a few possibilities:

* Χαρούμενη μέρα γάμου (Harouménē mera gámoy): This is a literal translation, meaning "Happy wedding day." It's perfectly acceptable but a bit straightforward.

* Καλό γάμο! (Kaló gámo!): This translates to "Good wedding!" or "Best wishes for the wedding!" This is more common and sounds more natural.

* Να ζήσετε! (Na zήsete!): This is the most traditional and widely used well-wish for a wedding in Greece. It literally translates to "May you live!" It's a wish for a long and happy life together. This is probably the best and most appropriate choice in most situations.

So, while "Χαρούμενη μέρα γάμου" is accurate, Να ζήσετε! is the most culturally appropriate and commonly used phrase to wish a happy wedding day in Greek.