Sincerely

• Letter sign-off (fixed formula) → Yours sincerely · Yours faithfully · Best regards
• I really mean this → truly · genuinely · honestly
• Without pretence (manner) → openly · honestly · in good faith

Compare:

• "It's genuinely free." → the freeness is real. No catch.
• "It's sincerely free." ❌ → not English. A price can't have an inner life.
• "I sincerely hope it's free." ✅ → my hoping is real.

The test: can you put I mean it in front of a person? Sincerely needs a human subject doing something — hoping, doubting, apologising, believing, thanking. If there's no person behind the word, you want genuinely.

• genuinely = "this thing is real."
• sincerely = "I mean this."

This is also why sincerely pairs with speech acts — apologies, thanks, condolences, promises — the things you can perform hollowly. The word exists to say: not this time.

• ❌ "Please accept my sincerely apologies." → ✅ "my sincere apologies"
• ❌ "He apologised very sincere." → ✅ "He apologised very sincerely."

Rule of thumb: before a noun → sincere. Before a verb → sincerely.

And one extra rule genuine doesn't have: sincere only describes people and the things people produce — an apology, an offer, an interest, a question, an effort, a smile. ❌ "a sincere bug", ❌ "a sincere discount".

• "Yours sincerely, Anna Petrenko" (British, named recipient)
• "Sincerely, Anna Petrenko" (American, any recipient)
• "Yours faithfully" (British, when you opened with "Dear Sir or Madam")

• Opened with a name ("Dear Ms Petrenko") → close with Yours sincerely
• Opened with no name ("Dear Sir or Madam") → close with Yours faithfully

Americans don't use faithfully at all — Sincerely, covers both. American English also allows Sincerely yours and Yours truly; British English wants Yours sincerely in that order.

• Capitalise the first word only: "Yours sincerely," ✅ / "Yours Sincerely," ❌
• Always followed by a comma, then your name on the next line.
• "Very sincerely yours" is a real American fossil, but it reads like 1955. Don't.

A ladder from warm to cold: Thanks → Best → Best regards → Kind regards → Regards → Sincerely → Yours faithfully.

Sincerely sits near the formal end. In a first email to a new client, it's safe. In the fourteenth message of a Slack-adjacent thread, it lands as distance — and after a disagreement, it can read as sarcasm. Most working email settles on Best or Thanks.

• "I sincerely apologise for the delay."
• "I sincerely hope this is the last time we redo it."
• "We sincerely regret any inconvenience."
• "I sincerely doubt that's the cause."
• "I sincerely appreciate you flagging it early."

In business writing it rarely means warmth. Compare:

• "I hope we can resolve this." → neutral.
• "I really hope we can resolve this." → warm, human.
• "I sincerely hope we can resolve this." → formal, and usually pointed.

The formality signals that the relationship has moved to the record. Native speakers hear it. Use it when you want that.

• "She spoke sincerely, and people believed her."
• "He sincerely believed the tests were passing." (he was wrong, not lying)
• "I think the offer was made sincerely."
• "a sincerely held belief" (fixed phrase, mostly legal)

That third-person use is the one that separates being mistaken from being dishonest — a distinction worth having in a postmortem.

• ❌ "Sincerely, I have no idea." → ✅ "Honestly, I have no idea." Sincerely does not open a sentence in English, even though sinceramente / sincèrement / щиро кажучи do exactly that in other languages. At the front of a sentence, English hears a letter, not an adverb.
• ❌ "That's sincerely useful." → ✅ "That's genuinely useful."
• ❌ "Sincerely thanks." → ✅ "Thank you sincerely." / "With sincere thanks."
• ❌ "I'm very sincerely sorry." → ✅ "I'm sincerely sorry." / "I'm very sorry."

• truly — "I'm truly sorry." The nearest neighbour. Warmer, less official; Yours truly is an American sign-off.
• really — "I really hope so." What people actually say out loud. Sincerely in casual speech sounds like you're reading from a card.
• honestly — flags candour and can open a sentence, which sincerely can't. "Honestly, it's not ready."

• genuinely — certifies things, not speakers. "Genuinely good catch" ✅ / "Sincerely good catch" ❌
• earnestly — sincere plus visible effort, and slightly literary. It can sound faintly comic: "he earnestly explained the rules of chess."
• wholeheartedly — sincere plus full commitment: "I wholeheartedly agree." Stronger, and only for agreement, support, recommendation.
• in good faith — the contractual sibling: "the offer was made in good faith."

• really — everyday. "I really hope so."
• honestly — flags candour. "Honestly, it's not ready."
• genuinely — certifies the thing. "Genuinely impressed."
• truly — warm, slightly literary. "Truly grateful."
• sincerely — formal, ceremonial. "I sincerely apologise."
• respectfully — official, hierarchical. "Respectfully submitted."

• "I sincerely apologise for the outage — the postmortem is attached."
• "I sincerely doubt this is a race condition; the logs point at the retry loop."
• "He sincerely believed the migration had run. The logs say otherwise."
• "We sincerely regret that the export was unavailable for six hours."
• ❌ "Sincerely good catch." → ✅ "Genuinely good catch."

Rough rule: if it's going in a PR comment, use genuinely. If it's going to someone who pays the invoice, sincerely is available.

• "I sincerely apologise — that estimate was mine and it was wrong."
• "I sincerely appreciate the flexibility on the deadline."
• "I sincerely hope we can agree on scope before the next sprint." (polite pressure)
• "We sincerely regret the delay and have credited your account."
• "Yours sincerely," (first email to a new client; switch to "Best" by the third)

• "I sincerely apologise for the state of the fridge." (mock-formal, affectionate)
• "I sincerely doubt he'll be on time." (dry, completely natural)
• "I sincerely hope you're not planning to cook that again." (teasing)

For real sincerity at home, English reaches for genuinely or really: "I genuinely forgot", "I really am sorry." Say "I sincerely apologise" to your partner and it sounds like a form letter — which, half the time, is the joke.

• Doubt: "I sincerely doubt it." (by far the most common spoken use)
• Cards: "Our sincerest condolences." / "With sincere thanks."
• Speeches: "I want to thank all of you, sincerely."
• Weather: "I sincerely hope this is the last cold week." (Chișinău, March, said through gritted teeth)
• Judging people: "Was she being sincere?" (adjective — the natural way to ask)

• "I sincerely apologise for the delay — here's exactly where things stand."
• "I sincerely appreciate your patience while we sorted this out."
• "We sincerely regret the disruption and have taken the following steps…"
• "I sincerely hope we can find a version of this that works for both of us."
• "Yours sincerely," (named recipient, first contact, British client)
• "Sincerely," (named recipient, first contact, American client)

Genuinely overused sounds insecure. Sincerely overused sounds cold — or worse, sarcastic. Repeated formality reads as distance being maintained on purpose, and after a disagreement your reader will hear it that way whether you meant it or not. Once per message, at most.

✍️ The signature line. Sincerely belongs at the bottom of a letter, under a person's name — never in front of an object. If there's no human behind it, the word has nothing to certify.

1. sincere — before the noun apologies, so you need the adjective.
2. honestly — sincerely never opens a sentence in English; at the front it reads as a sign-off.
3. genuinely — a price has no inner life. Sincerely needs a human subject.
4. sincerely — before the verb doubt, the word's most common spoken home.
5. Yours faithfully — no name in the greeting, so British convention takes faithfully. Yours sincerely is for named recipients; Sincerely yours is American.