Definition: to say that you will certainly do something or that something will certainly happen Level: B1
我保证明天给你打电话。
___I ___promise to call you tomorrow.
他真诚地向我保证他会帮忙。
___He ___promised me sincerely that he would help.
我保证我会按时完成作业。
___I ___promise that I will finish my homework on time.
