look it up!!! You could have found out how to get it and 10 other moves in the time it took you to ask both those times. Aromatherapy is an egg move for Chansey. I leave it to you to figure out who in the Fairy Egg group learns Aromatherapy by level up, therefore can pass it on to a chansey.
If you prefer Paralysis over Freeze, switch Ice Beam with Thunderbolt. For you guys who don't know what Serene Grace does, go catch a Chansey or breed it to find out.
Serebii is a great site. To find out what pokemon lear one of the egg moves, click on said egg move, and it will take you to a page that list all the pokemon that learn it through lv up, tm (I think), and egg. Oh, hot mustid. I agree, that's one of the best movesets, as long as the blissey has natural cure. If not, ice beam might be good. And one more thing. EV the blissey in defense. 252 evs. That way, with the wall of HP you have, not many attacks should kill you one hit.