The specific personality of a Pran is largely dependent on the way the master interact with her as fulfilling quests and undertake adventures together.
When you get your Fairy Pran, her personality is Cute, then it may change when she evolves.
Each personality makes the Pran interact with the master using different behaviors:

Yeah, I think it’s fun playing with you! I think that you might be one of my best friends, master! That makes me really happy! Let’s get going.
Some dumb Pran was running her mouth, so I socked it shut. I’m only sorry that she wasn’t sent straight back to the Pran Station.
I’m slightly bemused, master. I’m getting insulted because of my ears. It’s slightly gratuitous, isn’t it?
Yes, I really like being happy, too! Yay, this should be easy!
Hey, let’s see if you’re actually good for something. Hand over some cash. Um – please.
It’s usually cold in the mornings, so I warm myself up with a cup of tea, too! But sometimes I feel like I don’t need it – baby, I’m already steamin’ hot!