The way the Rašn explains the šsafikšof the gemara,that the reason that their is a yad since we learn out from a šma motzinošfrom Nedarim.What must be understud:
1)why learn out from a ma motzinu if we can't štransferšthe punnishment(šein onshin min hadinš?)
2)why does the rašn want to learn out from Nedarim, Nedarim itself must be learnt out from Nazir?
yehuda ARIEH arnstein
1) "Ein Onshin Min ha'Din" only applies when we have to derive, and transfer, the Onesh from the Melamed to the Lamed. Here the Onesh is already stated with regard to Kidushin; we are only learning from the Mah Matzinu what a Kidushin is.
2) After we learn the Hekesh of Nedarim to Nazir, we refer to both of them collectively as "Nedarim."