必然会发生的事;一定会成功的人(或事)If someone or something is a cert for something or to do something, he, she, or it is certain to get it or do it.
With all her experience she's a dead cert for the job. 凭她丰富的经验,她一定会得到这份工作的。
[ + to infinitive ] The Russian team is a cert to win the gold medal. 俄罗斯队一定会赢得金牌。