Paint the floor with an oil-based primer, then put new flooring in after you've confirmed the odor is gone.I've seen some pretty bad houses where cats were spraying against the wall.

(as alluded to above) If the odor is not properly mitigated that will cause ongoing problems.

My concern was someone may be sensitive to the odor.

You can't really appreciate it without the odor, but it's worth a shot.

@Amanda ThompsonI have never had a cat, but I have been told their urine can get into the floorboards or even into the concrete slab and that the odor is very hard to eliminate.

Sometimes it can take ripping out all flooring, trim, and fixtures, and adding layers of paint everywhere to block out the odor.

And the first thought that you had was, oh, OK, that's why I'm renting a C-class property with no sign of it ending to someone with good credit making 5X the rent, because she feels safe in that house next to the cop station and with a married landlord who doesn't give off the odor of eau de creep?

The last thing you want is to think you are finished and the odor lingers.

If the odor is not properly mitigated that will cause ongoing problems.

You can take off the baseboard (carefully, so you can put it back if that's not the source of the odor) and cut out a piece of sheetrock to examine.