You'll say that to your sincere and everlasting regret you didn't take him seriously.
If so, I am full of sincere and indescribable regret.
There was a touch of sincere regret in his tone.
"About his hair, all I can offer is my sincere regrets."
"I'm sorry about your people," she told him with sincere regret.
One of the committee men arrived to explain matters with sincere regret.
"I'm going to miss you, lady," she said with sincere regret.
I thought, if she won, she'd accept my apology and sincere regrets.
She gave the command without hesitation, but with sincere regret.
Accordingly, and with sincere regret, he had come to certain decisions.