Rather than clicking the first link, use this search query in Google or DuckDuckGo: "GTA San Andreas PSP ISO" "Internet Archive" zip This will lead you to user-uploaded archives with verified comments.
If you want the full, authentic GTA San Andreas experience on your Android phone, you have better options than using a PSP emulator: ppsspp gta san andreas zip file top download android
A device with at least 2GB of RAM and a quad-core processor is recommended for smooth performance. Rather than clicking the first link, use this