He maintained he paid his taxes.

  1. He maintained he’s innocent of failing to pay his taxes.
  2. He was found innocent of conspiring to kill the king.
    Are these sentences correct?

He maintained he’s’ is a mix of tenses. (he’s = he is)
He maintains he is…
He maintained he was…
Other than that, ‘innocent of failing to pay his taxes’ is an odd phrase. It would not be voiced in that way.

It would be more usual to say: He was found not guilty of failing/failure to …

That changes the sense though, as there is no indication in the original sentence that he has been found not guilty.

I think to maintain the sense a more usual saying would be: He maintained that he did not fail to pay his taxes.

How about: He maintained he paid his taxes.[YSaerTTEW443543]

TOEIC listening, photographs: Sitting around a table[YSaerTTEW443543]

That’s the most straightforward option. I’m trying to stay as close as reasonable to the original and assumed that there was a focus i=on the failure within the original accusation.