Does it mean "thank you for insult"? But who thanks for insult?:)
“You love her.”
Nick met his twin’s knowing gaze.
“More than I ever thought possible.”
Ralston leaned back in his chair.
“So why are you here, drinking scotch in my study?”
“Because she doesn’t love me.”
“Nonsense.”
The word came fast and frank. Nick shook his head.
“I appreciate your affront, Gabriel, but I assure you. Isabel does not love me.”
— Sarah MacLean "Ten Ways to be Adored When Landing a Lord"