Golbat evolves at Max Happiness
transferring a Pokemon resets its' happiness
so your Golbat probably isn't as Happy as you think.
A big misconception is that Pokemon Amie increases a Pokemon's Happiness... it doesn't.
This is how you find out how happy your Golbat is:
Visit the Friendship/Hapiness rater in Laverre City; Pokemon Fan Club; (northwest of the city, NPC: Pokemon Breeder) to find out how happy your Pokemon is in X or Y.
"It's amazingly friendly toward you! It must be so happy spending every day with you!" 255
"You must really like your <Pokémon> and always keep it by your side!" 200-254
"Well, I think you and <Pokémon> will be an even greater combo someday!" 150-199
"It's a little bit friendly to you… Something like that." 100-149
"Hmm…I think you have a lot of time ahead of you to get to know one another better." 50-99
"Don't tell me! Are you just letting it get knocked out in Pokémon battles?!" 0-49
This is what affects the friendship/happiness of your Pokemon and by how much depending on its' current friendship/happiness level.:
[It is hard to decipher - sorry about that - so pay attention to the commas].
Friendship: 0 to 99, 100 to 199, 200 to 255
Walking 128 steps (occasionally) +2, +2, +1
Massage in Cyllage City +30 (6%), +10 (20%), +5 (74%)
Using any vitamin +5/+6, +3/+4, +2/+3,
Using a Wing +3, +2, +1
Level up in battle +5, +4, +3
Soothing Bag from Super Training +20
Using EV-lowering Berries† +10/+11, +5/+6, +2/+3
Colorful Shake from the Juice Shoppe Pre-made: +1 per PokémonDollar.png100
Rare Soda from the Juice Shoppe +5/+6, +??, +??
Ultra Rare Soda from the Juice Shoppe +??, +??, +??
EV Juice from the Juice Shoppe +4
Perilous Soup from the Juice Shoppe ??, ??, ??
Using Heal Powder -5, -5, -10
Using Energy Powder -5, -5, -10
Using Energy Root -10, -10, -15
Using Revival Herb -15, -15, -20
Trading Reset to base friendship