je te souhaite un merveilleux voyage ma niece
Wonderful in French is merveilleux/merveilleuse
"your are welcome my beautiful niece"
safe trip mean passe un bon voyage in french
They have a wonderful day: ils/elles passent une merveilleuse journée; have a wonderful day (imperative mood) : passez une merveilleuse journée.
You can use the expression, "Bonne vacances!" in French, which literally means, "Good holiday," but would translate out to, "Have a good holiday!"
ma nièce my niece
her niece is translated 'sa nièce' (fem.) in French.
Gute Reise!
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
Je suis votre nièce
My favorite niece is 'ma nièce préférée' in French.
c'est magnifique !
my trip to france
You look wonderful = vous semblez merveilleux
Bon ete!
bon noel
un sommeil merveilleux