100% horizontal line will be the red axis in ‘Front’ view. So first adjust the axes, red along the direction you want to be perfectly horizontal. Then select ‘Front’ view.
Panning will keep red horizontal.
With adjusting the axes you could even tilt the R/G plane so blue will not be straight up but will lean backwards. This method will let you set up the perfect ‘Front’ view with a desired horizontal line.
You can even use ‘2 Point Perspective’
There are various tools for aligning views, there is the Position Camera tool, which you can click and drag to set a specific view.
Right click Align View is another.
Advanced Camera tools has other abilities.
None will be exactly the same as what you may find in other software.
In your example above I would probably right click on his forehead and choose align view.