All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
According to the preponderant opinion of Muslim Scholars Khul' (a woman forcing her husband to divorce her through the Muslim judge) is an irrevocable divorce. Thus, if you had not divorced her twice before this Khul' then you may take her back to your conjugal life provided you renew the marriage contract and offering a new dowry.
We warn you of two important matters.
First, one should not hasten in delivering divorce, rather he should think and take into consideration the problems he may face after divorce.
Second, when you propose to her after divorce you are just one of those who are proposing to her for marriage, so she has the right to refuse your proposal.
Allaah knows best.