Italian word sforzo comes from Latin evanescere, Latin *fortio, and later Latin *exfortio ((Vulgar Latin) I strain, strive.)

Detailed word origin of sforzo

Dictionary entry	Language	Definition
evanescere	Latin (lat)
*fortio	Latin (lat)
*exfortio	Latin (lat)	(Vulgar Latin) I strain, strive.
sforzare	Italian (ita)	(transitive) to force, strain.
sforzo	Italian (ita)	Effort, endeavour. Stress, strain.