i catched a zubat at level 7 with a pokeball and the message I get from the lady in the pokefan club is that it is very friendly towards me
so my question is what message I must get to make it evolve? (it fainted 1 time as a zubat)
the message must be:
"Your Pokemon is so kind to you! I'm a bit jealous!"
The first sentence should be about that, the second is exactly the same.
It depends on which game you are playing. Since you are playing Pokemon Platinum, you should get the following message:
"It's very friendly toward you. I can tell you treat it kindly."
Remember, just because you have the message doesn't mean you have a high enough friendship value to evolve it. The message appears at 200-254 friendship, Crobat takes 220 to evolve.
An in-depth article on friendship here.