Bébé, tu es superbe/fantastique
votre bébé est superbe
Stupefaction
Stunning in French is stupéfiant, épatant.
Piccola, sei splendida! is just one Italian equivalent of the English phrase "Babe, you are stunning!" The pronunciaton of the feminine singular phrase -- which translates literally as "Little one, you are splendid!" -- will be "PEEK-ko-la SEH-ee SPLEN-dee-da" in Italian.
There are many French words for 'stunning'. You might say 'C'est stupefiant' or impressionnante, sensantionnel or fantastique. If you were thinking of physically stunning, like a loud noise, you'd say 'C'est etourdissant'. (The e should have an acute accent).
'I love you babe' translates as: Je t'aime bébé
"babe" is "bébé", both for the baby and the affectionate name. But there are dozens of other affectionate names equivalent to "babe".
you say it si guarda stordimento
At my place, babe !
j'attends mon bebe
je t'aime chérie
manquez-toujours vous bébé