What is the religious ruling on a divorce oath being taken due to lying to someone?

It is not permissible to swear by anyone other than Allah, due to the prohibition of the Prophet, peace and blessings be upon him, regarding it. Whoever swears by other than Allah has committed shirk (definition) (polytheism), and the one who swore must repent and resolve not to repeat it. As for conditional divorce, the majority of jurists hold that it occurs upon the breach of the condition, while some scholars, such as Ibn Taymiyyah, are of the view that it does not occur, and instead requires an expiation for breaking an oath. It is advisable to refer to scholars and the Sharia (definition) courts in the questioner's country.