Barbed to compression fitting and EFI clamps do the trick every time. You cannot just put a slight flare on the end of the hard line, it will not hold as you found out.

Hardline and hoses contain thousands of pounds of pressure in the brake lines, less than 100lbs fuel pressure is nothing.

You can even get flared to barb fitting so you can flare your hardlines just like brake lines and properly attach the EFI hose to the barbed end.