gasdimming

(noun) The opposite of gaslighting. Gasdimming involves helping someone to realise that they are perfectly sane, lucid and are worthy of love and affection; particularly if they have recently been the victim of a gaslighter.

I'm so happy that Susannah's new boyfriend is gasdimming her, not like the last dickhead she went out with.

gasdimming

gaslighting via understating or underexaggeration

Person A: Didn't you only finish one problem of your math homework last night?
Person B: No, I finished all of them.
Person A: Are you sure about that? I looked in your bag and I saw that your homework was not complete.
Person B: Don't gasdimm me, I left that homework assignment at school today.
Person A: How am I gasdimming you?

Person B: You are manipulating me by questioning my powers of reasoning by understating what I finished. I didn't just finish one problem, I finished all seven problems, ask Ms. Goofyson, she'll say the same thing.
Person A: We'll see about that. (calls teacher)