That’s why I said above: “I’d rather see some sort of bead on the tube ends to aid in hose retention.”
This is known as a bead, just like those on coolant tubes and low pressure fuel tubing, et. al.:
There are hand held tubing bead rollers available. Some high end multipurpose flaring tools with the proper grip dies can do beads too. But they’re all a bit expensive for a one-off job. Maybe some parts stores that rent tools would have flaring tools? I wonder if a bubble flare at the end of the tube would work.
@Nevada_545 has a good idea with the flaring and union, but it wouldn’t necessarily have to be a double flare. Double flaring can crack the tubing if it’s too hard. Single flaring should be adequate for low pressure use, like for AN fittings. I’ve seen mention where some people have used compression fittings/unions successfully (if the tubing isn’t too hard to deform properly). No flaring needed.