"My country has 99% of people do not believe in virtual currency."
I know in the US they conducted a large survey about the popularity and use of cryptocurrency and 6 in 10 Americans that responded have heard about bitcoin but only 5 percent actually own it. So i guess it's possible that only 1 percent of the people in your country actually believe in or currently own crypto.
"How can they trust the virtual currency?"
At the moment i can understand why for many crypto is hard to trust especially after all the recent scams and exchange hacks. But I think as cryptocurrency matures it will become more widely adopted and more people will come to trust it.