Beautiful looks but stinking personality?

As a 21 year old how do you look past looks.

I understand everyone says looks aren’t everything and it’s so true but a lot of these people are older and more wise and been through a lot more life experiences.

I just lost my girlfriend of 2.5 years and she was absolutely stunning looking and eventually lost feelings. But looking back her personality stink she was a very rude angry person. Quick example walking in a public place that’s busy and she’s huffing and mumbling curse words under her breath because people are walking slow or whatever. Just the first thing that came to mind but a very angry, impatient and rude person at times. Not always! And ofcourse I still love her to this day she was my first but maybe was for the best we didn’t work out.

My question is how do you look past beauty and focus on inner beauty. I know i probably won’t find another girl as good looking as she is as I was punching a lot.