Mullberry tree spring cut

Hi all,
I would like to ask for advice.
I have a young mullberry tree. The issue is it's has two main trunks. I would like to remove the thinner one, as it is about tu rubb the more dominant one. Please do you have any advice how to deal with this? Or what would you recommend?
In one of the photos I made a line of how I think I should lead the cut.
Thank you!