区别就是两者意思是不一样，具体的不同如下

be sure中文意思是

确信;肯定;确定;

例句

The worst of it is that I can't even be sure if they received my letter.

最糟糕的是，我甚至不能确定他们是否收到了我的信。

make sure中文意思是

确保，务必，务请;尽力做到;深信，确信;证实;

例句

We make sure our clients get the best that money can buy.

我们确保客户买到最好的产品。