An (almost) never-fail method...
As someone else suggested, use a blow dryer to heat the hose...and be patient...it does take a little time. Lubricate both the inside of the hose and nipple...you don't want to use any oil or grease, 'cuz the last thing you want is a permanently lubricated hose connection that can work its way off the fitting over time. Most books will tell you to use dish soap, but KY surgical jelly works MUCH better. It's water soluble, so it dries out...and it's slipperier than anything else I've found.
