The most common and most likely answer to this crossword clue is the 4 letter word RUES
I've seen this crossword clue in Financial Times
R
U
E
S
More clues leading to the result RUES
- Is sorry about deception auditor’s picked up
- French ways to express regrets
- Herbs: bases for sauces, say
- Is sorry for heartless controls
- Regrets ways in 11
- Tours streets — and wishes one hadn’t?
- Regrets controls, a Liberal gone astray
- Is sorry to announce hoax
- Regrets deception on the radio
- Is sorry to say it’s a ploy
Buddy explains!

The straight part
We know that "French ways/regrets" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case french ways/regrets = rues.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RUES mean?
RUES verb- To cause to repent of sin or regret some past action.
- To cause to feel sorrow or pity.
- To repent of or regret (some past action or event); to wish that a past action or event had not taken place.
- To feel compassion or pity.
- To feel sorrow or regret.
- Any of various perennial shrubs of the genus Ruta, especially the herb Ruta graveolens (common rue), formerly used in medicines.