"Verification" in this context is the gold standard of accuracy. It means that the FPGA "core" (the file configuring the hardware) has been tested against original hardware and found to be cycle-accurate. It is not merely "compatible"; it is functionally indistinguishable from the physical machine. For the PC-98, a system with a complex architecture involving specific timing for the display controller (CRTC), unique sound chips (the OPNA YM2608), and proprietary DMA controllers, achieving verification is a monumental feat of reverse engineering. It ensures that software runs exactly as it did on the hardware, including the specific quirks and limitations that developers originally had to navigate.
Launch the core. Press F12 on your keyboard. Set the following verified settings: mister pc98 core verified