If you want to be totally professional.

And show you are in the driver's seat,You can write: 

"Thank you for the rent. As stipulated in our lease agreement, the rent is due on the first of each month. Appreciate your cooperation going forward, thanks!"

其他废话少说. （我们的合同5号之前收到都OK， 你去读一下你怎么

和她签合同的， 我写的英文是假设你合同里有每月1号）

所有跟帖： 

• 我的是3 号收到OK 她的意思是人难免有特殊情况 可是她每月都拖 才搬进去三个月 -westandingup- ♀ (0 bytes) () 11/10/2023 postreply 18:16:36

• 你不要管她啥意思. 口气坚决一点 -喜喜哈哈- ♀ (121 bytes) () 11/10/2023 postreply 18:24:32

• 是的 谢谢支持 -westandingup- ♀ (0 bytes) () 11/10/2023 postreply 18:30:57