If this guy doesn't have the funds to gamble his own money, certainly don't trust him with yours.
Hello everybody,
Should I lose, we can either restart and I will make it back, or I can give you your money back plus 20% in one weeks time. I can show proof of income.
This statement is extremely telling.
The guy is offering to pay back your money, plus 20% even if he loses... So basically he's willing to pay a 20% interest rate for a week loan.
If he's not an outright scammer, he is certainly dangerously addicted to gambling and will almost certainly burn through your money then vanish without a trace.