So what BS is going to come up to stop them from actually explaining things to him?
Honestly, the best way to do this is to just give him the classic isekai treatment. Skip the part about moving to a different world, and just give him the classic guild explination.
"Everyone has certain abilities which have rankings from _ to _. Most common people have a average rank of C for their abilities, and usually only have abilities pertaining to a few vague classifications like "combat" and "housekeeping".
It is extremely rare for people to have an "A" ranked ability. And those few who do are given significant preferential treatment, or may even become officially employed by the nobility, as their ability is powerful enough to have a notable to major impact on society and the lives of everyone around them.
Let's first get you measured (remeasured in Kurt's case) so that we can see where and what you specialize it. --- Gasp You have SSS rank is everything but combat?!?
Something like that would probably be enough since Kurt is pretty simple and wouldn't be able to deny the results of an "official guild evaluation". It would help if they gave him some examples, preferably of similar stuff to what he has already done, in order to give him an idea about what the value of the ability's rank represents before he is re-evaluated.
Then a bit of bad acting, them faking their surprise to learn his ability ranks, some reassurance that he won't be seen/treated differently by them, and finally having the "Master" step down and give the role to Kurt to hold onto for him. Use the excuse that his "current abilities are inferior in rank to Kurts", then have him go on a "long journey (forever) to improve his ability ranks so that he can not feel shamed by being the Master of someone more skilled than he is".
. Guild-chan could work too, like a 2nd best after Sakura.
