Fairly bad.
If the metal is bad from corrosion you may not be able to get a good edge. Here the corrosion is deep in the metal and it will probably chip as you hone.

If the corrosion is just on the surface you may be able to get an edge that will hold up to normal use.

That said, you will not keep the width of the blade. I would try bread knifing first. See gssixguns vids on how to to do this.

Getting to good metal on this blade will take some effort and a lot of luck.

I just gave up on a blade like this. Once I got the corrosion out I only had metal film to hone. The blade went to the wind chime box.

Good luck. Let us know how it goes.