Halakhah for Gittin 42:11

ר' יהודה בן בתירא אומר אין כותבין לא על הנייר המחוק ולא על הדיפתרא מפני שהוא יכול להזדייף וחכמים מכשירין:

— They deduce from them that [for a Get] we require something which genuinely cuts off the husband from the wife, as it has been taught: '[If a man says to his wife], Here is your Get on condition that you never drink wine, that you never go to your father's house, this is no "cutting off".<span class="x" onmousemove="('comment',' Because there is always some link between him and her. V. infra 83b. ');">⁹</span>

Shulchan Arukh, Even HaEzer