regretfulness

noun

1. (uncountable)The state or condition of being regretful.

   “Mervyn thought that he could detect a certain regretfulness in his companion's voice.”

   ““I’ll do what I can, monsieur,” he said, jingling the money. “But if there’s to be fighting, the Fleece will lose its good repute forever.” Mornay and Cornbury both laughed at the long face and hollow note of virtuous regretfulness and resignation in his voice.”

   “A desolating sense of loneliness kept driving him into the city's noisier and more crowded drinking-places, where, under the lash of alcohol, he was able to wear down his hot ache of deprivation into a dim and dreary regretfulness.”