It isn't as if she weren't/isn't pretty = It isn't as if she were/is ugly: Güzel olmadığı (çirkin olduğu) doğru değil (= Güzel olmasına güzel!)
I don't understand why she likes him so much, It isn't as if he's good looking at all: Onun nesine âşık bilmem, herhalde güzelliğine değil.