AbstractThis paper investigates the lexical representation of sincerity in Lithuanian epistolarity throughout the twentieth century. Drawing on data from the corpus of Lithuanian letters and employing the techniques of corpus, statistical and philological analysis, this paper explores the use, frequency and context of occurrence of the four sets of lexical stems: atvir- (‘open’, ‘frank’), nuošird- (‘sincere’, ‘honest’), šird- (‘heart’), and tikr- (‘authentic’, ‘genuine’, ‘real’). As each of these lexical stems foreground different semantic shades of sincerity, they are treated in this paper as lexical variables that inscribe different degrees of an author’s sincere attitude (stance) toward the addressee and the writing act itself. The findings suggest that in Lithuanian epistolarity the use of sincerity lexemes is constrained by the grammatical shape of the lexeme and genre-related factors, namely, formulaic vs. non-formulaic context. Frequent lexical inscription of sincerity lexemes in the speech acts of thanking, wishing and greeting suggests that sincerity (as a stance) is conventionally linked to these specific social acts. When these social acts are evoked in epistolary practice, they thus evoke a particular (sincere) stance meaning.