Why does my cockatiel hate other birds?

[Bird is the word]

I own a female lunito pearl cockatiel that hates other birds I have had her for around 3 years and got her at 7 months old but she has always disliked other birds. She live for one year with another cockatiel and whenever he would get close she would hiss at him and would do warning bites he unfortunately doesn't live with her anymore because he died due to a injury, but we still have another lovebirds who is really sweet to her but she hates him. How do I get her to start liking other birds because she is really aggressive towards them

 

[SilverBirds]

It's just her personality, which isn't really something you can change. Just like people, some birds love to be social while others prefer to keep to themselves. If she is healthy and happy just leave her be.