douceur de vivre -- ???
Bonjour! -- Good morning! (or) Good afternoon! (or) Good day! (or) Hello!
le mot juste -- the right word
la raison d'être -- reason for being
Bon appétit! -- Have a good meal!
un croissant -- a crescent roll (present participle of the verb croître -- to grow (or) to increase (or) to wax (as in the moon))
des hors d'oevres -- appetizers