regrettably

This adverb functions as a sentence modifier, typically appearing at the beginning of a clause to signal the speaker's emotional stance toward the information that follows. It carries a tone of formal apology or polite disappointment, making it highly suitable for professional correspondence, official announcements, or diplomatic social interactions.

While similar to "unfortunately," "regrettably" often implies a sense of personal or organizational responsibility or a wish that the outcome could have been different. It is rarely used in casual, spoken conversation among close friends, where "sadly" or "unfortunately" would feel more natural.