The true story is that he rejected Hilal's proposal, and wanna stay in Galatasaray much longer. The problem is that he wants increased salary from Galatasaray, which is impossible to happen. though he's Galatasaray's top scorer. Things getting even complicated when his contract becomes even shorter. That's the reason Napoli wanna recoup some money by selling him.
Even if he already rejected Hilal's proposal, but Napoli has not said no to the Hilal's proposal.
For a contract to be valid the player and both clubs wouid have to agree to the terms. Napoli cannot force Victor Osimhen to move to the Saudi Arabia League. He would have to negotiate his personal terms and sign contract. Galatasaray don't have the financial power to increase his salary, so he should consider that. His current wage is draining Galatasaray financial resources but the club is sacrificing because they need him. I just read a news that said Chelsea are close to signing the Nigerian striker.