Turns out the one spreading the rumors was Hashimoto, who did so at the behest of Sakayanagi. Shortly thereafter, Sakayanagi appears before Class C and she informs them she has evidence regarding the rumors about Ichinose.
You shared your secret with us 
now because you trust us, right?
بحتِ لنا بسرّكِ الآن لأنّكِ
تثقين بنا، أليس كذلك؟
Du vertraust uns doch und hast dich uns
deshalb geöffnet, nicht wahr?
Y nos revelaste tu secreto
porque confías en nosotros, ¿no?
Y nos has revelado tu secreto
porque confías en nosotros, ¿no?
Si tu t’es confessée,
E poi ce ne hai parlato
Você compartilhou seu segredo conosco
agora porque confia em nós, certo?
Хонами, ты ведь нам открылась,
 потому что доверяешь?
โฮนามิจังในตอนนี้เชื่อในตัวพวกเรา
ก็เลยยอมเล่าให้ฟังใช่ไหมล่ะ