The mesh fabric has slight stretch but should be considered non-stretch if using the size calculator.
The best way to ascertain if the fit is ok is to sit down in the pants when trying them on. They should feel snug but if you have difficulty sitting comfortably you should probably go up a size. Expect that the mesh will give a little after wearing the dress, so you may find it will stretch slightly to fit. The stitched satin waistband will also stretch 1-2cm after wearing.
The pants can be hemmed by your local tailor if required. They can be shortened at the hem or there is a seam at the knee that can be used to shorten the pant to keep the shape.
You should hand wash this piece due to the delicate nature of the mesh & dry on a hanger in the shade. Take care when leaning against any rough surfaces.
The laser cut petals may occasionally distress with wear, this is not a fault.