won't you

won't you是 will you 的否定形式，就如同 do you 和don't you一样。

放在句尾的do you 、are you 和 won't you 是反义疑问，前面是肯定，后面就是否定。比如
1）You don't like reading。
You don't like reading，do you？

2） You are not a teacher。
You are not a teacher, are you?

而且后一句与原句的意思是不变的

明白了吗？

前面是肯定，后面就是否定，比如
a. you will tell me the truth, won't you?
b. you won't tell me the truth, will you?
do you 也是一样的，前面动词是一般现在时的行为动词时，就用do
比如： you don't like me, do you?
are you 前面的动词要是系动词。
you are not a student, are you?

won't you 放在句尾是反义疑问句。
反义疑问句(The Disjunctive Question)
即附加疑问句。它表示提问人的看法,没有把握,需要对方证实。
反义疑问句由两部分组成：前一部分是一个陈述句，后一部分是一个简短的疑问句，两部分的人称时态应保持一致。
1．陈述部分肯定式+疑问部分否定式
2．陈述部分否定式+疑问部分肯定式
They work hard, don’t they?
She was ill yesterday, wasn’t she?
You didn’t go, did you?

are you going to do this, won't you?
you are