Things went smoothly for Eren after he introduced Reen to be the "incarnation" of goddess Echidna to Bisha.
Bisha couldn't undo the divine blessing herself. However, she did not dare to lie in front of Reen. She spilled everything about the current situation in the continent of Echidna, allowing Eren to get a clear picture of her world.
Bisha was also truthful about the problems and risks Eren would have to face if he were to visit Echidna as one of the Elder Seeds. The monsters were not quite on friendly terms with the Elder Seeds and potential Elder Seed inheritors.
Bisha told Eren about various prophecies related to the potential inheritor of the Elder Ichor's divine throne. These prophecies were related to various existing Elder Seeds.