Why would they disappear? You mean abductions? Why would that happen? There is actually a lot more of that risk happening with human traficking and pimping exactly because it's illegal, so women have to find a shady pimp who might abuse or sell them.

If it were legalized , then they could do the business independently , without a pimp, so the risks would greatly diminish, not to mention regular screenings so STD risk would be lowered too.

Prohibition creates violence, not the other way around. Look at the US alcohol prohibition era, and the current drug war. It speaks for itself.