From Longman Dictionary of Contemporary Englishfulfil a promise/pledge etcfulfil a promise/pledge etcformal to do what you said you would do SYN keep OPP break I’d like to see him fulfil his promise to reorganize the army. → fulfil
Examples from the Corpus
fulfil a promise/pledge etc• Instead, people earn both through a reinforcing cycle of making and fulfilling promises.• Pity he didn't fulfil a promise he made to Darlington Business Venture when he came up last November.• Young said he had fulfilled a promise he made when taking the helm in 1969. 