The calculated distance (air line) between Niefern-Öschelbronn and Bonn is approximately 146 miles respectively 236 kilometers.
By car or train, the actual journey to Bonn is certainly longer, as only the direct route (as the crow flies) between Niefern-Öschelbronn and Bonn has been calculated here.
Air line (approximately)
236 kilometers
127 nautical miles