You already have an open 'legal' option to be able to get it, don't be lazy, heh. ;} Not trying to be rude, but if it's the only viable way, then you're going to have to put on your working cap and do it. Or iono, lol. XD
Catch and level up a Miltank so that she can learn Heal Bell, then have a male Smeargle Sketch it. Breed that Smeargle with a female Snubbull/Granbull until you get a male Snubbull with Heal Bell. Breed that Snubbull with a Chansey, and presto! You have yourself a Chansey with Heal Bell, which can then evolve into Blissey when it's ready.
It's not the quickest way or simplest, but it's the only way to do it legitimately.