I wouldn't recommend the 85mm f1.2L simply because it's rather old technology already, the lens been around for maybe 10 years?
Lense technology has improved a lot since then, and you may be surprised that the 85mm f1.8 may be even sharper than f1.2L although it's not a L-lens. Also at f1.2, the DOF is already kinda of too shallow. Depending on how far you are from the subject, let say if you decided take a close-up facial picture of your subject, at f1.2, if you focused on the eyes, most likely the tip of the nose will oredi be out of focus.
What I will like to recommend is the 135mm f2.0L. It's a great portrait lens and comes comparatively cheap for a L-lens. The lense is extremely sharp, good colour fidelity and a good natural looking bokeh. Market price is about $1100 to $1300.