Hi shavua tov I have question about whether someone is allowed to back out of a verbal agreement being that they wouldnt have made the agreement if they knew a detail that they only found out about after making the agreement.

The Sages said: He Who exacted payment from the people of the generation of the flood, and from the generation of the dispersion, (i.e., that of the Tower of Babel), will in the future exact payment from whoever does not stand by his statement (Mishnah Bava Metzia 4:2). If one transacts with words only, it is appropriate for him to keep his word, even if he did not take any money, did not put anything in writing, and did not leave a collateral. Anyone who retracts, whether it is the buyer or the seller, although he is not required to accept “mi shepara”, he is lacking trustworthiness and the spirit of the Rabbis are not pleased with him (Shulchan Aruch Choshen Mishpat 204:7). Nevertheless, there are situations where one may back out of an agreement due to changes or misunderstandings. Please see Shulchan Aruch Choshen Mishpat 204. For practical advice on a specific case, please turn to your local Rabbi or Rabbinical judge with the other party.