When you meet a new sexual partner how do you know if they are STD free?

I ask and communicate the severity of lying. I've been lied to in the past with both casual and committed sex partners about when their last time happened. Now I tend to wait a few months to tested in between partners as well, just to give any STI a chance to show up on a blood test. But I don't have sex that often so it usually means I just get tested once a year or so.

Communication, asking, and if we really intend to get freaky with no protection, testing without a doubt. Always be safe, kids!

I like to communicate with my partner and trust them. I use protection regardless.

Asking would be the most direct and honest, but you have to trust them to tell you the truth.

A test is the best way to protect yourself.

I've never had to worry about it, since I've only had two partners and both were only ever with me. But I would have us get tested if that were a concern.