It's gambling, not trading or investing, so your confidence means nothing in gambling.
That paragraph sums it up. It's even captured in the last clause of your sentence. Luck is the major element in gambling as I continue to opine. Analyses, researches or anyone's level of confidence is just ceremonial and has little or nothing to do with winning bets.
You must afford to lose your gambling capital, but even so you must gamble very responsibly to minimize your potential loss.
No matter how a gambler feels they're confident on winning a bet, staking with what they won't regret losing should be paramount to them. Nothing should be treated with certitude to avoid over betting and the heartbreak that accompanies such over ambitious act. Gambling is a game of luck. I've yet to meet anyone who could prove that they won huge or a jackpot based on the research they made. Every gambler expresses shock and surprise each time they win and that's because it's a luck thing.