There is one thing I would like to tell you.
I have one thing I'd like to tell you.
There is something I would like to tell you.
There is something that I would like to talk with you about.
There is something that I want to talk about with you.
I have something I'd like to announce.
I have something I'd like to speak to you about.
There is something I would like to inform you about.
There is something that I would like to confirm with you.
I have one request.
There is one thing that I would like you to reconfirm.