To try on s.t. for fit [N-]; to fit [sika-]; to decide or determine what is sufficient, enough, or right [ma-].
A command in actor focus does not take -an, but statements and questions in actor focus do.
My shirt fits you and your shirt fits me.
Try on one of my shirts to see if it fits you.
Try my shirt on to see if it fits you.
It's up to you to determine how you want it.
You be the one to decide how much you will pay me.