Naturally, the torus object is rounded, which does give a nice look and feel to the pendant's hook. However, the rounded nature of the bottom may be tricky for the FFF/FDM printers. Looking at the slicing preview from the bottom up, I can see that perhaps there are some tricky overhangs for the printer.
In the following preview, I can see some places where lines of plastic would have nothing underneath it:
How our torus looks in Blender and how it looks in the slicing preview (looking from the bottom up).
Since no one sees the back of the pendant, we can flatten the bottom of that torus to help the printer out. To do that, we'll be getting more familiar with a technique called mesh modeling. We will change the shape of the torus by editing specific vertices.