Nothing will be 100% safe. Because GGG has shown it will ban accounts who traded with others who have been flagged.
But requiring them to have high level characters., so many challenges done, looking at their trade history to see how active they are, etc. Can help protect you.
Also putting an item for trade on the trade website that they then buy can help .
It also seems GGG will give people a second chance if caught, YMMV, but some people who have admitted to trading on here and promise not to do it again have gotten their account back.
Long story short, if you can't stomach having your account banned, trading on here for fg may not be worth itm