Under Federal campaign law, if that money arguably could have another purpose, such as protecting a company’s brand or protecting the family, then it’s not campaign money.
The current DOJ under this regime has so weaponized and politicized the Department of Justice that DOJ will arrest political opponents for crossing the street.
Even they wouldn’t take this case.
Thar will depend on the jury instructions. If the judge allows the question whether Trump had another purpose for paying the money - and Trump demonstrates that he did, the jury should acquit. If the judge doesn’t allow it, and he loses the case, it may be grounds to appeal. And if I recall correctly, the money was used to purchase the story rights from the woman - to prevent her from telling it her way to media companies and giving him control over how the story is told. If true he could in theory sell the story to a made for stream movie thus proving the payment was an investment not a campaign matter.