[He chooses to ignore the condescending tone of the red-haired man, as much as he'd like to just take offense to it and start a fight right here, right now. But he'd like to also see what the deal with this bridge was, so best not to burn it and the possible one he might be able to build here with Diluc as well. He's been curious about this man for a long time now...]

That's no way to greet someone. We'll be working together for this, and you just want to dismiss me out of hand like that? How unfair, hahaha.

[But there's no time like the present as they say, and Tartaglia checks his phone- it's almost time.]

Aren't you the least bit excited to see what will happen? Any minute now and this bridge is supposed to light up like a beacon- it's probably better if you can trust that I'll have your back when it comes.

[Absolutely using the word 'trust' here loosely, almost as if he's mocking him.]