Ok I don't own the Justice League but I do own the rest of the characters that you don't recognize and this is yet again for an upcoming story
Well the leader of the People's Gang got a surprise when Superman suddenly showed up at her window
"Superman what is it?"
"well I have something I want to give you not many people have it by the way and I actually want to keep it like that"
"what is it you want me to have?"
"this"
he hands her a lead box
"what's this?"
"well it's a lead box that has something potentially very dangerous to me"
"kryptonite, you gave me kryptonite why?"
"you never know if an enemy will try to take over me, so as a fail safe a select number of people have been given pieces of kryptonite just in case I go evil"
"Superman you barely know me heck we just met three days ago"
"I know but the League has informed me what you and your people have done for Metropolis even at the risk of your own life I can't think of anyone else I'd trust more who's also a civilian than you"
"are you giving this to me because I'm the leader?"
"that is part of the reason but the other part is that I've seen video footage of what you and your people have done and well, out of the entire group you risked the most"
"only because the others had to follow my orders"
"true but that's also another reason to trust you you don't ask anything from anyone that you wouldn't do yourself in fact if I saw the footage correctly the only reason you had someone else take care of an omega was because you were busy yourself helping some officers get kids and other civilians out of the path of weather wizards weapon plus you got powers because of livewire hitting you as you protected dozens of civilians like yourself soon after you had gotten those civilians to safety and didn't you take a hit from some debris of that wind?"
"I think you've made your point Superman I accept and thank you for trusting me"
"no problem"
and with that Superman leaves her apartment and she quickly puts the kryptonite in a safe place to be made into a locket at a later date that was lead lined so that she would only expose Superman to the kryptonite if need be plus no one would think twice of her wearing a necklace since she already needed one to help control her powers