No fund can guarantee an annual income of 100%. Your friend said that the things she bought in June last year have doubled now, which is also true. I have doubled the net value of two funds this year, but do you know that my funds have lost 15% in these four trading days?

No fund can guarantee an annual income of 100%.

The reason for doubling: the stock went up, and the fund bought the stock, so the fund also went up.