As we all know, Ben Affleck has yet to give us a true teaser of what his voice will sound like in Batman v Superman. Though recently, this happened.
One Ben Affleck's right is Seth Lee, a child actor, as they repeatedly saying "I'm Batman" on the set of Accountant. It may not be Ben's voice for Batman v Superman, but hey maybe it could. Whatever it could be, let's hope voice does get revealed at Comic-Con this year.