private and confidential

The letter was headed once again 'Private and Confidential'.

Inside was yet another envelope, carefully sealed with purple wax and marked 'Private and Confidential'.

For the best results these letters should be marked 'Private and Confidential' both on the envelope and on the letter.

She laid them on one side and didn't open the envelopes with "Private and Confidential' written upon them and heavily underlined.