I am sure about that.这句话语法有误吗?

没有啊、那I am sure of that 呢？形容词 a. 1.确信的,有把握的[Z][F][+(that)][+wh-][(+about/of)]I'm not sure whether our team will win. 我不能肯定我队是否能赢。 We are sure of his innocence. 我们确信他是无辜的。 2.一定的,必定的[Z][F][+to-v]She is sure to write to you. 她一定会给你写信的。 3.确实的;可靠的One thing is sure, he won't let you down. 有一点是确定的,那就是他不会让你失望。 Exercise is a sure way of losing weight. 运动是减肥的可靠办法。 4.稳健的;稳固的一般of后面应该直接加名词吧、