From Now On...

Princess Isabella was already strong in the Peak-Level Martial Master Stage that she could fight with Martial Sage Experts, but it was never seen as she never got to fight properly other than the one time she battled Keith Ethren, and especially Algos Yantra who was much stronger than a simple Law Sea Stage Expert. 

If she successfully entered the Martial Sage Stage, on top of her original prowess, the pure power granted by the tempering of her own laws would make her powerful enough to instakill opponents at the same level and battle Mid-Level Martial Sage Experts equally, and perhaps even enable her to struggle against High-Level Martial Sage Experts!

Davis was well aware of the chasm between levels in the Eighth Stage. Being able to battle across a level meant the laws she comprehended were of top quality compared with normal cultivators remaining in the same Law Intent.