Whenever bad things happen to you,please always be smile.You

smile是动词,所以be后不能接原形
there are so many people care about you
句子出现两个主要动词 are,care
所以care前最好加 who

1. care about you 改为 caring about you . 这是分词做定语修饰people.
2. about you .And I want to 应改为 about you , and I want to .这是并列词and 连接的并列句,不应该用句号.

Whenever bad things happen to you,please always smile (去掉be).
You know,there are so many people who (加上一个who 本句应该是个定语从句。原文少了关系词)care about you.
And I want to see the smile on your face,to（加上一个...

there are so many people care about you改为caring

Whenever misfortune befalls you, please keep smiling. You know, so many people care about you. And the last thing I want is to see your smile wiped off your face, to notice your laughter fades away. I pray for luck and fortune to accompany you. After all, I just want you to happy.