aufrichtig
sincere
Honest and without falseness; corresponding to true feelings or convictions. A person or their statement can be sincere.
Ich möchte dir meinen aufrichtigen Dank aussprechen.
I would like to express my sincere thanks to you.

sincere
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sincere
Honest and without falseness; corresponding to true feelings or convictions. A person or their statement can be sincere.
Ich möchte dir meinen aufrichtigen Dank aussprechen.
I would like to express my sincere thanks to you.

The word is made up of 'auf' and 'richtig' (right/correct). You can think of it as 'upright' or 'straightforward,' which describes the meaning of honesty and directness well.
Er ist ein aufrichtiger Mensch, dem man vertrauen kann.
He is a sincere person whom you can trust.
'Aufrichtig' (sincere) is often used in fixed combinations to strengthen feelings or statements. Typical examples are 'aufrichtiger Dank' (sincere thanks), 'aufrichtiges Beileid' (sincere condolences), 'eine aufrichtige Entschuldigung' (a sincere apology), or 'aufrichtiges Interesse' (sincere interest).
Wir möchten den Hinterbliebenen unser aufrichtiges Beileid aussprechen.
We would like to express our sincere condolences to the bereaved.
'Aufrichtig' (sincerely) can also be used as an adverb to describe a verb. It then answers the question 'How?'. In this form, it remains unchanged.
Er hat sich aufrichtig für den Fehler entschuldigt.
He sincerely apologized for the mistake.
real / really
'echt' and 'aufrichtig' can both describe feelings or words that are not put on. 'echt' sounds more general and more colloquial; you can speak of 'echte Freude' (genuine joy), 'echtes Interesse' (genuine interest), or 'ein echter Freund' (a true friend). 'aufrichtig' fits especially when someone honestly means what they say or feel. It sounds somewhat more serious and is often used with apologies, thanks, or personal statements. When the main point is inner honesty, 'aufrichtig' is more precise.

Nach dem Streit hat er sich aufrichtig entschuldigt.
After the argument, he apologized sincerely.
Ihre Freude über den Besuch war echt.
Her joy about the visit was genuine.