me and my firend were battle to raise eeves level of like ness to max to alow us to trade it and then let it trade in to espeon. but it didnt evolve.

I actually had this happen to myself (and I got ticked off).

Whenever a Pokemon is traded, its Happiness is reset to a fixed value. The value of happiness depends on the Pokemon (for most Pokemon, it's 50). Your friend will need to evolve it by happiness in his RSE game (or yours, or whatever), and then the Eevee will evolve once it grows one more level.

I repeat, its Happiness is reset once traded.
- DNA

Psypoke also has a guide that covers pretty much everything about Happiness. Oh, and by the way, most pokemon reset to 70 happiness, not 50.