The logic is good, but I’d make the sizing recommendation clearer and remove the slight contradiction around choosing M vs. L:
Revised version:
Sarah’s waist falls within the S size range, while her hips fall within the L range. Because her measurements fall into different sizes, we recommend choosing the M for a more sculpted, compressive fit.
If her hip measurement is toward the upper end of the L range, we recommend sizing up to L for additional comfort and room through the hips—even though her waist measurement alone indicates an S.
For customers who want more waist compression or a stronger waist-training effect, we recommend choosing the faja size that properly accommodates the hips and pairing it with one of our waist trainers.
You may also choose the Shorts from our Underwear Collection and pair them with your preferred waist trainer for targeted waist compression while maintaining a comfortable fit through the hips.