Chinese people communicate very subtlely but are serious in their actions. Unlike MOST OTHER COUNTRIES (Western countries, Middle Eastern, India etc who are loud mouths with no action behind it)
I think if Wang Yi, who is basically at the core of power in China, is telling Netanyahu to his face that China will defend Iran, then that means China is going to take serious action in doing that. Otherwise, you would have heard a mealy mouthed talk about "being concerned" like you got from Modi.
We'll see what happens. I think this means China will be supplying Iran with critical military supplies at the VERY LEAST.