一封邮件发样品发错了,有很委婉很诚恳的道歉,不知道这样写行不,Dear Maria,I am very sorry fo

您的信语法上没问题,但感觉委婉、诚恳不够.We will try our best像只是在try,不够积极；而且不该要对方理解您的过错!如果是我,我会这样写：
Dear Maria,
It is absolutely unforgivable for us to send you the wrong sample. However, I would like to express my sincere apology for our blunder that may have cost you a lot of inconvenience.
We are now rushing with no efforts spared to make the correct sample to ensure delivery today in good order. You shall receive the tracking number of the sample immediately after we get it.By the way, there is no need to return the wrong sample.
I apologize again for our mistake. Best regards!
XXX

因为客人可能一天要看数十封或上百封供应商邮件，所以外贸函电一定要简洁，道歉一句话就够了，关键是你的后续补救措施要及时，只要及时修正了错误，一般客人就原谅你了，毕竟是做生意而不是赌气
1） 客人最关心的是正确的样品什么时候收到，所以这是关键一点
2） 在回复这封邮件的时候你答应客人今天发出样品，同时你就应该想到发完快递后把快递单号给客人，以便他查询。
Dear Maria,

Dear Maria,
I am very sorry for my mistake and the inconvenience that must have caused you.
We will try our best to speed up making your sample, and it will be certainly delivered today in goo...

Dear Maria,
I am very sorry for my mistake and the inconvenience brought to you.
We will try our best to speed up making your sample, and sure to deliver it today in good order.
For the sa...

1. my mistake causeing inconvenience to you
2. put you to trouble

Dear Maria,
I would like to express my apologies for my mistake in making the sample.And I also feel much sorry for the inconvenience that must have brought to you.
We will try our best to spe...

亲爱的玛丽亚，
我很抱歉，我的错误，并认为必须给您带来的不便。
我们会尽力加快使您的样品，并可以确保交付今天的良好秩序。
对于那些您发送样品，没有必要派回。
我觉得对不起你造成很多麻烦。
您的谅解将受到高度重视
最好的问候...

金山词霸翻译吧