The affix ḍāc comes after the word satya followed by kṛ 'to make' when not meaning 'to swear'.,
The word सत्य means 'truth' as opposed to 'falsehood'. Sometimes it means to swear, as in the sentence \सत्येन शापयेद् विप्रम्\ ॥ This latter sense is prohibited. Thus सत्या करोति वनिक् भाण्डम् \the merchant concludes the bargain of the goods i. e. he settles that he will purchase these wares\. Why do we say 'when not meaning to swear'? Observe सत्यं करोति ब्राह्मणः \the Brahmana swears\.,