Tradução - Francês-Inglês - On s'inquiète pour sa petite chérie, hein ?

La phrase anglaise contient deux interjections ("so" et "Huh" alors que la traduction n'en contient qu'une. Je pense que ça nuit à la restitution de la phrase originale.

sa petite chérie - his little sweetheart

The intention of the whole text is : "You worry about your little sweetheart, huh?", but written in a mockery tone. That's why I choose "we" .
In the french text, as there is no context, you can not be sure whether it should be his or her little sweetheart. The only thing we know is that the sweetheart is a she.

I think Ienab you are right with "we" in french, but I think isn't understanding as well in english

Je pense Ienab que vous avez raison avec le "nous/on" pour le français mais je pense que cela ne sera pas aussi bien compris en anglais.