urn over a new leaf 的意思是重新开始(改过自新,过新生活) .
英文释义:means to get a new start ,to change everything about yourself .
例句：
Now let's turn over a new leaf.
现在咱们从头开始（建立较好关系）.
I'm turning a new leaf ,No more drinking ,No more smoking,It's a healthy life from now on.