"I don't give up easily and I haven't given up in my heart."
He had spent his entire life doing good things for other people, he said.
"One day I'm going to stand here and tell you 'I told you so'."
The District Court trial earlier this year heard evidence from Kim Dotcom of a lunch at the Dotcom mansion, which was also attended by Dotcom's wife Mona, and Banks and his wife Amanda, on June 5, 2010.
Dotcom told the hearing there was a conversation about a donation to Banks' 2010 mayoral campaign and ways of making it anonymous.
Dotcom and his wife denied there was anyone else at the lunch.
At the Court of Appeal in Wellington today, Banks' legal team presented signed affidavits by two American businessmen, David Shaeffer and Jeffrey Karnes, who said they were also at the lunch.
"We know for a fact that two Americans were there throughout and their very presence is denied by Mr and Mrs Dotcom," Mr Jones said.
Mr Jones read out a statement by Mr Karnes that said there was no conversation at lunch about splitting a $50,000 donation cheque in half.
But Crown lawyer Paul Dacre said there were "certainly" discussions about the donations, if not at lunch, at some stage.
"Evidence shows Mr Banks did know about the donation ... that his inaction shows there was no donation recorded in his return."
It was not clear when Banks knew about the donations, he said.
"It comes back to the charge that Mr Banks knew the returns were false."
Banks told police he had told Dotcom that he could make a donation anonymously, Mr Dacre said.
He also told police he did not tell his campaign team about the donation because he had told Dotcom he could make it anonymously.
Banks, former National Party president Michelle Boag, former Act MP John Boscawen and Banks' former chief of staff Chris Diack were in court today watching the proceedings.
Justices Ellen France, John Wild and Forrest Miller reserved their decision.