The calculated distance (air line) between Castelnovo ne'Monti and Sassuolo is approximately 20 miles respectively 33 kilometers.
By car or train, the actual journey to Sassuolo is certainly longer, as only the direct route (as the crow flies) between Castelnovo ne'Monti and Sassuolo has been calculated here.
Air line (approximately)
33 kilometers
18 nautical miles