約束をふむ
to make a solemn promise with someone
から約束
to keep one's promise―keep one's word―be true to one's word―be as good as one's word―keep an appointment―keep to an agreement―abide by an agreement
約束すること
the act of exchanging promises
to fulfil one's promise―keep one's promise―keep one's word―make good one's promise―redeem one's pledge