Dear Yong Peng,
OYP> I think you are right about "no" being an emphatic.
"No" here is a first person plural enclitic (Acc., Dat., Inst., Gen.).
I think here it is Genitive "our".
> DN25 Udumbarika Sutta CSCD55/PTS3.40
> Aya.m kho no, bhante, antaraakathaa vippakataa; atha bhagavaa
> anuppatto.
For, Venerable Sir, this our mutual talk is left unfinished,
and now has reached the Blessed One.
Mettena cittena, Dimitry