Here's a rule of thumb on scams: know what the risk-free rate is (in the American case, the benchmark would be 10-year U.S. Treasury note rates), and know deep in your heart that any[0] return above that bears risk.
The 10-year note currently yields a fraction above 4%, as of the last auction[1]. That means that anything that has the potential to return above that also has the potential to lose money; and generally, the more potential for higher returns, the more risk. Anybody claiming to give you a "quick, safe return" on your money is lying about at least one of the quick, safe, or return; i.e., a scam.
[0]: Very rarely, there are true arbitrage opportunities or some other situation where someone's cleverness leads to outsized risk-adjusted returns. "You" are probably not that someone.
The 10-year note currently yields a fraction above 4%, as of the last auction[1]. That means that anything that has the potential to return above that also has the potential to lose money; and generally, the more potential for higher returns, the more risk. Anybody claiming to give you a "quick, safe return" on your money is lying about at least one of the quick, safe, or return; i.e., a scam.
[0]: Very rarely, there are true arbitrage opportunities or some other situation where someone's cleverness leads to outsized risk-adjusted returns. "You" are probably not that someone.
[1]: https://treasurydirect.gov/instit/annceresult/press/preanre/...