never mind (none of your business): ne t'occupe pas / ce n'est pas tes affaires never mind (don't worry): ne t'inquiète pas, pas de souciJamais l'esprit.
Uhm, You can't really say that literally but you can say you will never be alone wish is أنت لن تكون وحيدا أبدا or I will never let you alone أنا لن أدعك وحيدا...