Is the expiation for an oath (kaffarat al-yameen) obligatory for someone who swore to speak to a specific person on a specific day, but that person did not show up at the appointed time, and what is the amount of this expiation if it is obligatory?

If the object of an oath becomes impossible due to a normal impediment that arose after the oath was sworn, expiation (kaffarah) is obligatory in all cases.

The one who swore the oath is required to offer an expiation for an oath, which is to feed ten poor people, or clothe them, or free a slave. If he cannot find any of these, then he must fast for three days. However, if his intention at the time of swearing the oath was to specify the action to a certain time, then nothing is required of him if the condition is not met.