(╥﹏╥)(╥﹏╥)

Technically, it's the MC's past incarnation that was lovers with the priest guy(his incarnation). So, the saintess (MC's past incarnation) has some control over the MC's conscious or exists in some form within the MC. Hence she jumped to save him from Hades and said those love words in ancient language. It would all have been better explained to Hades but the problem is hades understood those love words, so now he is hurt and it daunts to him that the MC might just have been lying all along and using his trust on her.

OMG

btw thanks