Are jokes forbidden, and if so, [if it is due to the presence of lying in them], then why are they considered forbidden as long as the listener knows it is a jest and does not consider it a lie?

Fabricated jokes are forbidden, even if they are mentioned in jest and the listener knows they are false, because the basis of their prohibition is that they are lies. This is based on the saying of the Prophet, peace and blessings be upon him: "Woe to him who speaks and lies to make people laugh thereby. Woe to him! Woe to him!" Lying is not permissible whether in seriousness or in jest.