Is there a nice way to ask or tell someone they should get tested for STIs or STDs?

I'm dating someone and they've had sex a few times before. I'm a virgin so I'm quite positive I'm clean. However it's not that I don't trust them I just don't trust the other people they've been with and I'd rather be safe than sorry because there is skin that is not covered by condoms that can also carry some sort of infection. Help please?