speak for truth?

[bosun]

Hello!
I wonder if the following sentneces make sense to you. If you find any mistakes, can you correct them for me?

1. This report speaks for truth.

2. wemust pay attention to the fact that he is always late for work.

3. We must give special attention to the fact that he is always late for work.

4. He will come back withihg a week( or in a week? what is the differnce??)

5. I am supposed to go to back to Korea because of the company-wide organizational changes. I deeply appreciate your kindness and feel sorry to part.

[JSmiley]

they are all fine,

within a week, and in a week, are also exactly the same.

at the very end, "to part" should probably be "to leave" but if you make it "to part ways" or "that we will part" you will sound very smart indeed!!