Hello,
Could you please whether there is any problem in the sentence grammatically which I wrote below?
-I wish I hadn't said anything about the girl who will come here tomorrow.
Thank you...
Looks good!
It looks fine to me too. The only suggested change I would make would be to change "who will come" to the present continuous suggesting the future. The following just sounds more natural to me:
I wish I hadn't said anything about the girl who's (or who is) coming here tomorrow.