Mangrove Monitor Health Issues

Hello all. I'm buying an (allegedly) breeding pair of Mangrove Monitors from a local pet store. They're around 2 feet long, and according to the shop owner around 2 years old. I'm not able to sex them of course until I purchase them, but the owner says they're one male and one female. The male one (if it is indeed that) is extremely active and the picture of health, super-alert, vocal and hissing when held, voiding his bowels to resist handling, etc. However, the supposedly female one is scrawny, her hip bones are showing, her tail and body are thin, and she seems very lethargic, although when placed on a floor or other surface she becomes more active (this doesn't seem to apply to the too-small cage she's kept in). Her back and neck also shows scarring and tissue damage. I understand that Mangrove Monitors are rough in mating, so I'm wondering if the female's health is due to that, or some other concern.

Anyone have any ideas?