Well, at least that's a very clear demonstration of what's wrong right off the bat. Not knowing about the specific curse going around, Chizuru actually looks rather taken aback when he says that - mostly since she didn't expect him to be so forward about it. She's seen him emotional before (though more sad than frustrated, but still) and that sure didn't come out that easily.

But a honesty curse would explain it.

"Ah.. no!" She looks like she's struggling to find the right words for a moment, not wanting him to feel awkward yet at the same time--

Well, at the same time she can't help but blurt out the truth too after a moment or two.

"It's alright! You don't have to apologise, I don't mind at all.. I-I mean, it's slightly surprising, but I'm actually rather glad that you're being honest with me about it so I don't have to worry about what could be wrong."

At least it's not far enough from something she'd usually say that it doesn't stand out to her yet.