Is it obligatory to fast three days as an expiation for an oath for someone who swore falsely to reconciliation, without intending the oath, and then swore again not to contact someone, also without intending the oath?

A Muslim should reduce the number of oaths he takes. An oath not intended as such, or one that did not cross the mind of the swearer when uttered, is considered a 'laghw' (idle) oath, for which there is no expiation. Examples include saying "No, by God" or "Yes, by God." This is based on the Almighty’s saying: {Allah will not impose blame upon you for what is unintentional in your oaths, but He will impose blame upon you for what your hearts have earned.} It is recommended to reconcile with one's sister and treat her kindly, even if she has wronged you. For whoever treats his relatives well and endures their mistreatment will have a supporter from Allah.