Does a divorce that the husband made conditional on selling gold without his knowledge take effect? What is its expiation? And what are the consequences, knowing that this is the second time the husband has sworn by divorce?

The second divorce of the wife occurred due to the fulfillment of the condition upon which the divorce was suspended, which was the wife selling the gold, if the intention behind the oath was that she should not sell it neither immediately nor in the future. However, if the intention was that she should not sell it within a specific period and she sold it thereafter, then no divorce takes place.

If you took your wife back during her 'iddah (definition) (waiting period), she is your wife, and one divorce remains. But if you took her back after the 'iddah ended, then the return is not valid, and a new contract is required with a new dowry, a guardian, and two witnesses. What transpired before the contract in this manner is considered intercourse by شبهة ( شبهة - doubt/ شبهة of legality), whereby the child is attributed to you, and the prescribed punishment is averted from both of you.