Maybe bc she's obv a good observer like a damned hound dog and is already living for this drama
She knows zero percent about the relationship between them how can she just assume everything so perfectly.
Assumptions are inherently imperfect, but if they happen to be correct then what's the problem. People guess about others relationships everyday and sometimes if they're good enough analysts they'll hit gold. Her position at work and at such a high level would mean that she's highly intuitive and attentive to other people's needs and minds, so this doesn't seem out of place to me. Plus she could also just be a fujoshi letting her imagination run free; she does seem to enjoy pushing buttons.
Why stereotype her though? Oh yeah It’s that one fujo female character in Yaoi. She attentive but certainly he is that character that can hide his thoughts and without showing it in his face.
Idk why the people in the comment section think the secretary is trying to get these two together. She does not know yet why he has his sudden change of heart.