Did Ye Wenjie actually tell Luo Ji the dark forest law?
No, and this is the detail most readers get wrong. At Yang Dong's grave, Ye Wenjie did not hand Luo Ji the dark forest conclusion. She gave him two axioms of cosmic sociology: survival is the primary need of civilization, and civilization keeps growing while the total matter in the universe stays constant. On top of that she named two concepts, the chain of suspicion and technological explosion. That is the entire deposit.
The famous conclusion, that the universe is a dark forest full of armed hunters, is something Luo Ji derived himself over the long years of the Wallfacer Project. Ye Wenjie did not give him an answer. She gave him a seed that could grow into one, and the distinction shapes everything that follows.
Why did Ye Wenjie choose Luo Ji specifically?
Because he was the perfect container for a dangerous idea. On the surface, Luo Ji was simply a friend of her late daughter Yang Dong, which gave Ye Wenjie an innocent reason to talk to him. But he was also an astronomer who could grasp the math behind the axioms, a cynical outsider with no faction, and therefore someone the Trisolaran world was not watching closely. Choosing a famous scientist would have exposed the seed to the sophons. Hiding it inside the least likely person was the whole point, which is why the Trisolarans were later baffled when the Wallfacer Project chose him too.
Why did she only tell him half?
Because the sophons can read every word humans say out loud, but they cannot read a human brain. Any conclusion spoken directly would have alerted Trisolaris instantly. By breaking the idea into two abstract axioms and two terms, Ye Wenjie passed something that looked like harmless academic chatter. The lethal derivation happened only inside Luo Ji's head, the one place the sophons could not reach. She engineered an encryption that could only be decoded in a human mind, with the axioms as ciphertext and Luo Ji's reasoning as the key.
Would Ye Wenjie be hunted by Trisolaris for this?
No. To the Trisolaran world, what she handed over was indistinguishable from idle philosophy, with no stated threat and no visible hostility. She was also the spiritual leader of the ETO and a hero to the Adventist faction, so no side had any motive to move against her. She disguised the most dangerous step in the trilogy as a parting gift to her daughter's friend, planting the seed while keeping herself completely clear of it. Understanding this graveyard scene is what makes the full dark forest derivation make sense as a two-generation relay that slipped past the sophons.