promiseI promise that I'll be home before dark.
guaranteeI can't guarantee that the operation will be successful.
give (someone) your wordformalHe gave me his word that the job would be finished on time.
assure"Don't worry, your car will be ready tomorrow", the mechanic assured him.
swearI didn't know what happened, I swear.
pledgeWe are asking people to pledge their support for our campaign.
resolveI have resolved to lose ten pounds.