Is it permissible to lie about one's nationality to facilitate marriage to a righteous woman, knowing that customs and traditions prevent marriage between different nationalities?

Lying is forbidden in all its forms due to the corruption it entails, and both the Quran and Sunnah (definition) have warned against it. Allah Almighty says: "O you who have believed, fear Allah and be with the truthful." And the Prophet, peace and blessings be upon him, said: "Hold fast to truthfulness, for truthfulness leads to righteousness, and righteousness leads to Paradise... And beware of lying, for lying leads to immorality, and immorality leads to the Fire." The prohibition of lying increases when it involves deceit and trickery. Therefore, it is not permissible for you to claim to be of a certain nationality to gain the approval of the girl's family for marriage, because that involves unjustified deceit and lying, and because of the expected future harms.