Formal:
* "Bienvenu(e), mon amour." (Literally, "Welcome, my love.") This is the most direct translation and works in formal situations.
Informal:
* "Bienvenue, mon cœur." (Literally, "Welcome, my heart.") This is a more affectionate way to say it.
* "Bienvenue à toi, mon amour." (Literally, "Welcome to you, my love.") This is a more poetic way to say it.
* "Je suis heureux/heureuse de te voir, mon amour." (Literally, "I am happy to see you, my love.") This is a good option if you are expressing your happiness at seeing your loved one.
For a more informal and casual way to say it, you can use:
* "Bienvenue chez nous, mon chéri/ma chérie." (Literally, "Welcome to our place, my darling.")
The best way to choose the right phrase depends on the specific situation and your relationship with the person you're talking to.