If you go to Thingiverse you can use the customizer app to place 4 messages on 4 hearts. These will then be in .stl format. If you have a package like Vectric’s Vcarve Desktop, you can create the tool paths to carve these out. The app has an option to put a hole in the heart so that you can make it into a necklace.
Openscaddad has some other CNC projects in a collection.
He’s the greatest!!!