When does the above apply? When both nazirites remain silent or the matter is doubtful for them. If, however, one of them says: "I did not become ritually impure," even if two witnesses testify that he became impure, he does not bring a sacrifice because of their statements. His statement: "I did not become ritually impure," can be understood to mean: "I will not bring a sacrifice [because of] impurity, because I have already asked [a sage] to absolve my vow." Thus he is not contradicting the witnesses and a person's word is accepted with regard to his own person. If, however, he remained silent or was in doubt concerning the matter, he should bring a sacrifice even when the cause is the testimony of one witness, as we explained [above]
Similarly, if a witness tells a person: "You took a nazirite vow in my presence" and that person disputes the matter, he is not liable for anything. If he does not dispute the matter, he must observe [the restrictions of] a nazirite vow because of his statements.
Even if [a person] told two others, "I saw one of you take a nazirite vow, but I do not know which of you it was," since [neither of them] dispute his statements, they both must observe a nazirite vow, because of his statements. If a person observed a nazirite vow because of the statements of one witness and drank wine or became impure [due to contact with a corpse] and two witnesses administered a warning, he is given lashes even though the fundamental dimension of the testimony is dependent on one witness.