Gould's sure-fire, been there, done that,
hose fitting solution.

Got a heat gun? The kind with a tapered barrel on the end and suitable for
removing varnish? If so, you're almost home.

Turn the heat gun on low. Stick it in the end of the stubborn hose. When the
hose gets really flexible, stuff the heat gun in just slightly to increase the
diameter of the hose. Withdraw the heat gun. You should have a hose with a very
slight "bell"on the end. Soap up the male part of the joint and see if you can
just barely force the hose onto it. If so, you've got a good fit. If not, apply
slightly more heat and pressure to expand the hose some more. Shoving the hose
on when it's still hot is probably helpful, too. Perhaps it contracts just
slightly when cold.

Once fitted, use two hose clamps.

No heat gun? Buying a heat gun is much cheaper than paying some guy $150 CDN to
do the job for you, and you'll then have a handy tool. :-)