JRPGs are made in Japan and WRPG are made in western countries. That is the only true difference. Everything else is just correlation, what games from each region tend to entail.
WRPGs tend to be about open worlds and choices. The developers are trying to make you feel like you are the protagonist and you have a say in what happens in the game.
JRPGs tend to be more about telling a very specific story. The developers want you to play through the very specific story that they crafted.
Obviously this isn't always true.
For example Dark Souls is a JRPG, but if the developer was never listed, 90% of people would have thought it was a WRPG. Big open world. No set specific path. Story you piece together on your own.
Recently JRPGS have not been too popular so there haven't been any big cases of western developers copying their design, but it still happens. For example Dust: An Elysian Tail.
