Avoir une belle journée
Aveti o buna ziua!
Well, there are many ways to say wonderful in French. Here are some...Magnifique, merveilleux, fabouleux, fantastique, but there is no way to actually say the word wonderful in French. =D
J'esp
They have a wonderful day: ils/elles passent une merveilleuse journée; have a wonderful day (imperative mood) : passez une merveilleuse journée.
'Have a lovely day' would be translated 'passe une bonne journée' in French.
j'espere que tu a (vous avez) un bon jour
un puits à souhaits
c'est magnifique !
The sentence structure is a bit awkward. It would be better to say, "Have a wonderful day ahead" or "I hope you have a wonderful day ahead."
You look wonderful = vous semblez merveilleux
"Je te souhaite la paix."
You can say "You too!" in response to someone wishing you to have a good day.