ticket (n.)
票

例句：
In order to ride the bus you must purchase a ticket.
你必须要先买车票，才能上公共汽车。
 

go back on
背叛、出卖、毁约

例句：
He would rather die than go back on his friends.
他宁死也不出卖他的朋友。

To tell you the truth.
跟你说实话吧。

对话：
A: Do you think this dress is suitable for me?
B: To tell you the truth, it's too big for you.

A：你觉得我穿这衣服合适吗？
B：跟你说实话吧，你穿太大了。