2 aniyatas
aniyatā 1
"yo pana bhikkhu mātugāmena saddhiṃ eko ekāya raho paṭicchanne āsane alaṃkammaniye nisajjaṃ kappeyya, tamenaṃ saddheyyavacasā upāsikā disvā tiṇṇaṃ dhammānaṃ aññatarena vadeyya pārājikena vā saṃghādisesena vā pācittiyena vā nisajjaṃ bhikkhu paṭijāmāno tiṇṇa dhammānaṃ aññtarena kāretabbo pārājikena vā saṃghādisesena vā pācittiyena vā, yena vā sā saddheyyavacasā upāsikā vadeyya, tena so bhikkhu kāretabbo, ayaṃ dhāmmo aniyato."
Not to be found alone with a woman in a remote place that can arise suspicions about a sexual intercourse. A bhikkhu is found alone with a woman in a place remote from others' sight, where a sexual intercourse is possible (in a place hidden behind a wall, curtains, etc.). They are seated together, being not in the presence of another woman or man who is able to understand. If a trustworthy person, seeing this bhikkhu, brings an accusation before the saṃgha, whether it concerns a pārājika, a saṃghādisesa or else a pācittiya, the accused bhikkhu finds himself in the case of indefinite fault and he is duty bound to admit the fault that he has committed.
By being isolated with a girl born on the same day, a bhikkhu is not spared from committing this fault.
aniyatā 2
"naheva kho pana paṭicchannaṃ āsanaṃ hoti, nālaṃkammaniyaṃ, alañca kho hoti mātugāmaṃ duṭṭhullāhi vācāhi obhāsituṃ, yo pana bhikkhu tathārūpe āsane mātugāmena saddhiṃ eko ekāya raho raho nisajjaṃ kappeyya, tamenaṃ saddheyyavacasā upāsikā disvā dvinnaṃ dhammānaṃ aññatarena vadeyya saṃghādisesena vā pācittiyena vā, nisajjaṃ bhikkhu paṭijānamāno dvinnaṃ dhammānaṃ aññtarena kāretabbo saṃghādisesena vā pācittiyena vā, yena vā sā saddheyyavacasā upāsikā vadeyya, tena so bhikkhu kāretabbo, ayaṃpi dhammo aniyato."
Not to be found alone with a woman in an isolated place that can arise suspicions about conversations on lustful subjects. A bhikkhu is found alone with a woman in an open place within the reach of others' sight, but from where one cannot hear what is being said, and about which one can imagine that the conversation bears a lustful character. They are seated together, without the presence of another woman or man able to understand. If a trustworthy person, seeing this bhikkhu and being in the position to suspect a saṃghādisesa or a pācittiya, brings an accusation before the saṃgha, the accused bhikkhu finds himself in the case of an indefinite fault and he is duty bound to admit the fault that he has committed.
The fact that it is not possible to hear the words said in a place non remote from sights may be due to the surrounding noise, the presence of a transparent wall (glass), or else to a remote distance (starting from twelve cubits, approximately 6 meters).
Source