Jaina alone maybe not, but Jaina and Uther together might’ve been able to steer Arthas in a different direction, especially if Jaina and Uther took it seriously when Arthas tells them about Mal’Ganis. A big component of his fall was how he tried to take down Mal’Ganis on his own, because he felt isolated and unable to trust anybody else.
If nothing else, I think Arthas could’ve been persuaded to hold off on hunting Mal’Ganis until the plague business had been properly taken care of. In this scenario, Arthas still falls, but it’s much further down the line which changes the result pretty dramatically – when he returns to Eastern Kingdoms as a Death Knight, Lordaeron isn’t in a weakened state of confusion and doesn’t have cultists actively working to strengthen the Scourge, meaning it’s no longer a given that Arthas succeeds in conquering it.