here is what I used....Like I said it worked but it used to sweat fluid because there is actually a hose within a hose on high pressure lines. the inside hose is liquid tight and the outside hose is for strength, that hose was 15 years old and those sharp barbs would cut through the inner hose after being stretched over the barbs then clamped hard.
I also tried a splice tube made out of 1/4" brake line, I double flared both ends and put 6 hose clamps....it spit it right off.
But then this was a leveler hose so it had all that pressure to lift and hold the motorhome up, and for a couple years I lived with a replaceable rag wrapped around it. Yours is for a slide, so this may work fine.
BTW >>ONLY use the best quality fuel injection hose clamps you can buy..I found out the hard way about cheap hose clamps.
good luck, Tony