Historical clue formulations

• "Cross my heart!" — 2022-06-21
• "Seriously!" — 2021-07-10
• "Cross my heart and hope to die!" — 2017-09-05
• "This ___!" (fighting words) — 2016-10-27
• "Really!" — 2016-06-17
• "Honest!" — 2016-04-04
• "Cross my heart and hope to die" — 2015-09-27
• "Seriously!" — 2013-06-06
• "Really!" — 2011-02-24
• "No lie!" — 2010-09-16
• "No fooling!" — 2009-09-22
• "Honest!" — 2008-04-24
• "Honest!" — 2007-12-16
• "Honest!" — 2005-07-25
• "Honest" — 2002-02-17