At OneLook, we are the only dictionary with an entry. DCDuringTALK 11:46, 5 July 2009 (UTC)
To tell you the truth, I can't make up my mind. I'm not sure there isn't an idiom here, though I don't think as a fully conjugating form. If it is an idiom, it would be like to make a long story short/long story short. We have entries that are conversational directives. I'm just not sure that this one needs an entry. DCDuringTALK 12:18, 5 July 2009 (UTC)
To tell the truth, I know this phrase from Czech and it strikes me as a non-SOP, meaning "to be frank", "to be honest", or "frankly", being placed at the first position in the sentence like last but not least. But the headword should possibly better be "to tell the truth", as "to " here means "in order to", rather than just showing an infinitive, or that is at least how I read it. Czech translation: "Popravdě řečeno", "Abych řekl pravdu".--Dan Polansky 17:28, 6 July 2009 (UTC)
Yes, I think the English usage is very similar. As entered, the phrase is a verb, which seems wrong. I can't quite hear any form except infinitive and, possibly, gerund. I believe that it is more like a synonym of the adverb frankly, but only used appositively, bracketed by punctuation. It is some kind of comment on the following statement or the entire following conversation. At COCA, there are 990 uses of to tell the truth. Most of them seemed very literal SoP. But of that group, 206 were bracketed by punctuation. They seem to represent the widespread usage in question. Even more common is to tell you the truth (416). Bracketed by punctuation, tell the truth gets 97 hits, tell you the truth gets 28, tell ya the truth gets 2.
I am not at all sure that these terms all meet WT:CFI. The forms with "to" seem SoP to me. Moreover, there are numerous other forms of equivalent conversational use: "to be frank", "speaking frankly", "to be honest", etc. All seem SoP, non-idiomatic. DCDuringTALK 18:17, 6 July 2009 (UTC)
Forms without the "to", they seem more likely to be non-SoP.
I am going to convert the RfD to rfd-sense at the verb. I think I will enter under the idiom PoS, a non-gloss definition. Getting similar treatment will be tell you the truth. I think the presence or absence of "you" makes a difference, though I'm not sure exactly what. In both cases I will include the form with "to" in the sense line as a non-wikilinked defining term. DCDuringTALK 18:17, 6 July 2009 (UTC)
Okay, provided "to be frank", "to tell you to truth", "to be honest", "speaking frankly", "frankly speaking" are all only set phrases rather than idioms and thus not kept, is there a place at Wiktionary, say an appendix, to which they could be filed? Thus, when I (or any other user) want to know what set phrases are synonymous to "to tell you the truth", I look into that appendix instead of in the main Wiktionary space. What if I create an appendix "Appendix:English set phrases"? --Dan Polansky 10:01, 7 July 2009 (UTC)
I wouldn't object to that, but I'd like to hear from others about which of these should be in principal namespace. DCDuringTALK 14:55, 7 July 2009 (UTC)
After the renaming I would add tell the truth and tell you the truth because each appear as standalone terms. The are readily attestable and are not quite SoP, IMO. In this idiomatic use they are not inflecting verbs. DCDuringTALK 15:41, 7 July 2009 (UTC)
I think people might not have realised that I was only nominating the verb sense, not the "phrase" sense. I've gone ahead and cleaned it up. Take a look, feel free to modify, but kept. Mglovesfun (talk) 10:45, 23 October 2009 (UTC)