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Why don't you prove your skills in the open and offer some free picks for everybody mr big shot?

Much more trustworthy than you trying to make people believe in your skills like you do it and trying to rebuild your scratched reputation.
I doubt he would ever do that. He probably isn't good at sports betting but has some decent writing skills so he decided to whip up a shitty little e-book. Even if he did and people made a couple of bucks off it, it still wouldn't prove anything because he might have just got a couple of lucky bets.