[The cheeky response earns Aizawa a tired look. Really? You're going to go that route? Shigaraki almost decides to turn around and refuse to give him an answer when Aizawa continued to speak.]

I don't think it's unnatural for you not to speak. You have nothing to say to him if he doesn't accept. You've left the hero world, remember? [Aizawa's silence meant acceptance of the League and maybe a bit of humiliation on the teacher's part that a hero was so easily swayed.] And if he does accept? Well... of course you'd be allowed to speak to each other. We're all equals here in the League.

[Because in theory- they both would have already pledged loyalty to Shigaraki and the League. What purpose would they have to plot sabotage? Shigaraki isn't a fool of course and would never let the two work together until he could fully trust that they weren't just planning to take the League out from the inside.]

You haven't really convinced me and if it doesn't matter to you, I guess you can remain quiet.