Hi Zora! 안 is a negative. '안' of 안녕하세요 is different from 안 of '안' 이뻐. In the words 안 이뻐, 안 is a negative. In economical reasons, you use “안” other than “아니” You read the sentence “아니 춥다.” I ask you to read it quickly. more quickly more quickly. “아니 춥다” is changed into “안 춥다” As you say, “안” is a short form of “아니” 안 춥다. (춥지 않다.) 비가 안 온다.(비가 오지 않는다.) 안 이쁘다.(이쁘지 않다.) Here, the word '안' modifies the verb, “춥다 and 온다 etc.” I hope that helps. Feel free to contact me if you don’t understand it.

It does have something to do with it, yes. ~안 can be a negation in any way shape or form. 난 안 예뻐. - I'm not pretty. 난 = I 안 = negation 예뻐 ~ 예쁘다 = pretty