Reference for Sotah 39:2

תרי תנאי ואליבא דר"ע

The question was asked, how is it if she said: 'I refuse to drink' through defiance and she retracts and says 'I am willing to drink'? Is it that since she said: 'I refuse to drink' she admitted 'I am unclean', and having presumed her self to be unclean, she is unable to retract; or perhaps, since she says 'I am willing to drink', she evidences that she first spoke in terror? — The question remains unanswered. Samuel's father said: It is necessary to put something bitter into the water. What is the reason? Scripture declares, The water of bitterness<span class="x" onmousemove="('comment',' Num. V, 18. ');">¹</span>

Jastrow

Jastrow