How To Make Your Kitten Happy?

i’ve tried everything and my kitten is still ignoring me. i’m at a loss and don’t know what else to do. please help!

My cat isn’t afraid of anything except…himself? I bought two cats from the same litter, one male (2-3 years old) and one female (1 year old). The older cat was fine with other animals such as dogs, birds, etc., but the younger female does not like them or any other creature in general. She will run away when someone approaches her cage while she is sleeping or playing with her toys; however, she will let people pet her while she is sleeping/playing on their lap without running anywhere. My question: can anyone tell me why this happens to only certain animals depending upon their breed? Also how can we get over this barrier that keeps us from being able to communicate with each other? How should we go about trying to get along better if our species has never been exposed to each other before? Thank you very much for reading this message!!!