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.
I thought I read somewhere just recently that there was an email by her denying there even was an affair...
Something between her and Cohen.
Seems like that would be a mighty big wrench in the gears...