The calculated distance (air line) between Sīlat al Ḩārithīyah and Nablus is approximately 20 miles respectively 32 kilometers.
By car or train, the actual journey to Nablus is certainly longer, as only the direct route (as the crow flies) between Sīlat al Ḩārithīyah and Nablus has been calculated here.
Air line (approximately)
32 kilometers
17 nautical miles