She did say that, but do u really think it's that easy, forgiveness has to be earned. Try thinking from her POV, zain had wronged her not once, but thrice, he didn't trust her to even try to find out the actual culprit, he trusted the police saying it was aaliya more than aaliya herself. Not that aaliya hamesha sahi thi, i don't think woh jo gauhar ka nikah rizwan se krne ki zidd pakray bethi thi woh sahi thi. Even after aayat and rizwaan's nikkah, she wanted aayat to leave rizwaan, that wasn't her decision to make, woh aayat ko samjha skti thi, apna nazariya bata skti thi, but osko bhi aayat ki baat sunni and samajhni chahiye thi, toh aaliya is no saint, neither is zain, sub say galati hoti hai, gunaah bhi hotay hai, but jub realize hojaaye and bunda suchay dil say tauba karay toh Allah (Subhanahu wa Ta'ala) bhi maaf krdaytay hai, tou hum kya cheez hai.
Besides, aaliya said woh maaf karaygi, oskay saath jaayegi ya nhi aisa nhi kaha, ab zain aisa samjhay toh woh oski soch ki problem hai, jese pehle thi, jb osnay aaliya k sirf, "haan, me or rehaan," kehne pr poori nikah ki kahani banali thi. At least I think there will be a catch.
Still, we'll have to wait and watch to be sure. Until then keep watching BI, and keep loving zaya :)