Cherie
"Sweetheart" is most often rendered as "Chérie" (fem.) and "chéri" (masc.) in French.
The Latin word for sweetheart is puella. The word sweetheart in Spanish is novio, in Italian it is Tesoro, and in French it is amoureux.
Mon chéri.
Cheri/e
In Cajun French, you can say "cher(e)" or "mon cher" to mean sweetheart.
Merci chérie
cheri occupés.
amoureux
bien-aimé
ma petit chou
Là où êtes vous amoureux
Vous êtes les bienvenus amie.