the gemara says that we are lenient to allow one witness because it might lead to the women becoming an aguna. But then the gemara says that it's not a leniency, it's a stringency. Then it brings the cases of one witness becoming disqualified by the husband, but the 2 witnesses can't be disqualified. It sound like if there is one witness that can be disqualified, it's a leniency and 2 witnesses is the stringency because it can't be disqualified. So what's the stringency?
Daniel Abraham,
Stage 1: Mishum Agunah - We are lenient to allow a Get with even one witness who knows it is Kosher so that she should NOT remain an Agunah (if this Get is rejected).
Stage 2: No, it is a Chumra - meaning it's worse to allow such a Get which can afterwords be ruined by the husband's complaint (this is called Chumra since something can occur that we don't want) but if we accept only two witnesses the Get will remain intact, since he can't ruin two witnesses and this is therefore a Kula something which keeps the situation without problems.
All the best,
Reuven Weiner