One promised can be replaced with several synonym words depending on the context of the sentence. If the sentence is in past tense, then synonyms such as committed, assured, pledged, or swore can be used. These words convey the sense of a binding agreement or vow that was made. Alternatively, if the sentence is in present tense, synonyms like avowed, declared, affirmed, or vowed can be used. These words represent a promise that is currently in effect and may or may not have been kept yet. Using synonyms for one promised can help add variety to writing and convey different shades of meaning to the reader.