Demai4: 1
הַלּוֹקֵחַ פֵּרוֹת מִמִּי שֶׁאֵינוֹ נֶאֱמָן עַל הַמַּעַשְׂרוֹת, וְשָׁכַח לְעַשְּׂרָן, וְשׁוֹאֲלוֹ בְשַׁבָּת — יֹאכַל עַל פִּיו. חָשְׁכָה מוֹצָאֵי שַׁבָּת — לֹא יֹאכַל עַד שֶׁיְּעַשֵּׂר. לֹא מְצָאוֹ, אָמַר לוֹ אַחֵר שֶׁאֵינוֹ נֶאֱמָן עַל הַמַּעַשְׂרוֹת: ,,מְעֻשָּׂרִין הֵן“ — אוֹכֵל עַל פִּיו. חָשְׁכָה מוֹצָאֵי שַׁבָּת — לֹא יֹאכַל עַד שֶׁיְּעַשֵּׂר. תְּרוּמַת מַעֲשֵׂר שֶׁל דְּמַאי שֶׁחָזְרָה לִמְקוֹמָהּ, רַבִּי שִׁמְעוֹן שְׁזוּרִי אוֹמֵר: אַף בְּחֹל שׁוֹאֲלוֹ וְאוֹכְלוֹ עַל פִּיו.
[If] one purchases fruit from someone who is not trusted regarding tithes, and forgets to tithe it, and asks [the seller] on the Sabbath, he may eat [the fruit based] on [the seller’s] word. [With] the onset of darkness at the departure of the Sabbath, he may not eat [it] until he separates tithes. [If] he did not find [the seller], [and] someone [else] who is not trusted regarding tithes said [to him]: ‘‘[The fruit] is tithed,’’ he may eat [it based] on his word. [With] the onset of darkness at the departure of the Sabbath, he may not eat [it] until he separates tithes. [Regarding] terumas maaser of demai which returned to its place, R’ Shimon Shezuri says: Even on a weekday, one may ask [the seller] and eat [the fruit based] on his word.