You were experimenting with sports betting and found yourself profitable with your strategy. However, you can’t raise a bigger bankroll to generate larger profits. Then there’s this one guy who believes in you and is willing to lend you money, of course, with interest, almost like a loan shark rate. The question is, would you see this as an opportunity or just a trap?
You can use whatever money you like to gamble but a borrowed one is something I wouldn't advice anyone to do gamble with. The dangers involved in this are quite enormous considering the fact that gambling isn't really something that has a definite outcome and putting a sum of money that doesn't belong to you into it is absolutely ridiculous. If you end up losing the bet you are going to end up in debt
The major question is, will that guy that believe in you to win, be able to contain it when you lose the money he gives to you to gamble with, since gambling is somewhat not predictable and the certainties of you losing is very high so for that, taking a loan to gamble with is not a welcome idea to many of us.
Gambling should be done basically for fun, and if you win, just know that you were lucky and you did not win based on your level of skills of whatever.