Lighting Situations
The hardness and softness of light depends on the size of the source and the distance of it from the subject.
Here the size of the window was reduced to get the harder lighting on the left which corresponds to using a small light instead of a softbox.
There was a fair amount of ambient light which is lighting the 'shadow' areas to give quite a pleasing balance without the reflector in the third example.
Small window small lightsource
Hard lighting
Large window/softbox
Soft lighting
Hard lighting balanced with reflector
Caught in direct sunlight
A narrow window with light background
Narrow window, light background, and soft reflector
While a mirror or silver foil is a powerful reflector it can be too strong
Using a white board from right hand close to the subject for a softer and balanced result
Moving the board further away results in a smaller and slightly harder fill light