The possibility of Zaniolo leaving As Roma is quite small, because Roma's relationship and situation makes him comfortable. But if Mourinho had another player they wanted to replace Zaniolo, Roma might let him go. But I haven't heard about it now, about there will be a replacement for Zaniolo next season. So I'm still pretty sure he's still going to stay.
Yep, his current situation in AS Roma makes him comfortable, never heard bad rumors. That player never stated to plan moving to another club in the near future, so it is a strong sign that he feels happy at AS Roma. So far, there is no issue that Mourinho wants to sign a player that has the same position as Zaniolo. Mourinho seems satisfied with him, he must play regularly and be a key player in the lineups if he didn't get injured. Based on this fact, he has no reason to leave.
I don’t know if Roma is interested in selling this player but if they get a good enough deal, I think they will surely think about it. But as of now, I doubt they are willing to sell this player.
On the other hand, Juventus is actually a bit desperate to get a capable attacker in my opinion. They have done everything to balance the team and I have to say they have done well to fix the issue in midfield and defense.
Well, they did not have too many problems in the defense. But if they are willing to sell de Ligt I think it will be a bit problematic for them. But they do need an attacker so that they don’t have any problems scoring goals in the next season.