Is it permissible to conclude a marriage contract with the intention of divorce without informing the wife, and is one who intended to make something permissible after the contract then divorced sinful?

The intention to divorce does not invalidate the marriage contract. Similarly, the intention of tahlil (making a divorced woman lawful for her first husband) that occurred after the contract does no harm. What matters is the intention at the time of the contract. So, if the intention of tahlil arose during intercourse, it does no harm. As long as he did not marry the woman with the intention of tahlil [from the outset], then his marriage to her is valid if it fulfilled the conditions and pillars [of marriage], and there is no sin upon him for intending tahlil after the contract. If he consummated the marriage with her and had intercourse with her, then divorced her, she becomes lawful for the first husband after the expiration of her iddah (definition) (waiting period).