The term used in philosophy and speech act theory is "truth value." I have also seen "truthfulness" and "veracity," but "truth value" is the most common and is considered a primitive (see first example).

["speech act"+"truth value"]: 28,400 refs
["speech act"+truthfulness]: 13,100 refs
["speech act"+veracity]: 10,300 refs

... 1 ILLOC) FSS) (implies *top* (all ILLOC SPEECH-ACT)) (define-primitive-concept ... (and ADJECTIVE-PROPERTY)) (define-primitive-concept TRUTH-VALUE (and ...
svn.mindswap.org/pellet/trunk/test_data/dl-benchmark/tbox/fss-gcis.tkb

According to PS, **our intuitions about the truth-value of utterances** of sentences ( ... skepticism) is that it incorporates Speech Act Pluralism (SPAP). ...
folk.uio.no/hermanc/docs/PSFinal.pdf

**truth value** might vary with the context of assessment as well as the context ... the context in which the speech act (or other use of the sentence) ...
sophos.berkeley.edu/macfarlane/makingsense.pdf

On What Sort of Speech Act Wittgenstein's Investigations Is and Why It Matters ... One can of course to some degree **assess the truthfulness** of the ...
www.hfac.uh.edu/phil/leiber/wittgens.htm

Speech Act Theory in Thomas Reid
Elements of Speech Act Theory in the Work of Thomas Reid ... **promise or contract), veracity (by testimony), or fidelity (by engagement or promise)**. ...
wings.buffalo.edu/philosophy/faculty/smith/articles/reid.PDF