"Sincerely yours" is a popular closing phrase used in formal communication. However, it can become repetitive and generic over time. As such, it is vital to know other synonyms that could add a personal touch and warmth to your message. Some synonyms include:
1. Best regards
2. Warmly
3. Cordially
4. With gratitude
5. Yours truly
6. Respectfully
7. Kind regards
8. Regards
9. Yours faithfully
10. With appreciation
In conclusion, using one of these synonyms can help to express your sincerity better and add some warmth to your communication.