بَارَكَ اللَّهُ لَكَ، وَبَارَكَ عَلَيْكَ، وَجَمَعَ بَيْنَكُمَا فِي خَيْرٍ
Barakallahu laka, wa baraka 'alayka, wa jama'a baynakuma fi khayr
Qu'Allah te bénisse, répande Ses bénédictions sur toi et vous réunisse tous deux dans le bien.
Say to newlyweds after marriage
The Prophet (PBUH) would say this dua for newlyweds, asking Allah to bless their union.