Question

I want my chansey to evlove but I'm not sure how to tell if its ready or not.

Answer 1

There's a girl in Goldenrod City, in the house next to the department store, she will say "It looks really happy! It must love you a lot" if it's happy enough to evolve.

Comments

You can check it using Pokétch App 6, Happiness Checker, obtained from woman in Eterna City pokémon center. Two big hearts to max happiness.
OR
Visit Dr. Footstep living on rt.213. I´m not sure what he has to tell you but Pokémon has max happiness when he give you a Footprint ribbon.