It's your own opinion that will answer that question, even Manny will tell that he take the huge cut and donate the other part of his earnings people will still have their opinions, but like what you mentioned about how generous Manny was, it's known by many from the Philippines, we can't remove the fact that he really providing help with many charities.
True that but, of course, we can't avoid people being skeptical about this statement of Manny. Unless there is proof that Manny really gives the proceeds to the promised charity, people will keep on doubting the statement. I just come to believe it because, as you stated, and from several media outlets that proving that he gives funds to charities and government relief programs.
The amount of his earnings from this fight is just a little portion of his wealth, so if he said that he will donate everything
then so be it.
Manny Pacquiao came from a poor family, so I believe he can relate to all the sufferings of poor people, that is why he is lending out his hands every time he has a chance to do so.