英文请求信的最后一句该怎么说

much appreciated 正确的用法
most appreciated 勉强还可以，mostly appreciated 错误用法了

看要求的是甚麽了
除了你的说法，还有很多
例子
Thank you for your understanding
looking toward your approval
will be glad to have your agreement
would appreciate very much that you take a closer look at the proposal
.... 等等 。。

我不太理解的你请求信的具体意思。
不过类似这种英文信函最后一句应该是：looking forward to ... ...
你的说法也可以，感觉mostly用的有点别扭，改成：We/I really appreciate your understanding.

Your understanding will be much appreciated.

We are looking forward to your early reply.

Hope to hear fromyou soon.

Many thanks for your kindly permit.