The TL on Page 30, panel 2 sounds lopsided.
So the context is: Momo has been really generous to Kotone (With Momo asking for nothing in return) so Kotone is repaying the kindness to Momo via gifts and dates.
The last balloon from panel 1 starts it off: "Being so dense that you don't understand"
Which continues off with the awkward "Why it someone would be kind to you and wanting nothing in return, when you've really helped them out, is definitely one of your charms"
I haven't seen the raws, but shouldn't it be:
"Being so dense that you don't understand--"
"--Why someone would be kind to you after you've helped them so much while wanting nothing in return, is definitely one of your charms"
That fits the point Kotone was going for better, at least IMHO.
I think it's just that the word "it" in the second bubble shouldn't be there.
Or, an "is that" has been omitted that should have been right afterward. ("...that you don't understand, / why it
is that someone would be kind to you...") But if you took out the "it", and considered both speech bubbles as one ongoing sentence, it still works, yeah.
And yes, there should be a comma after "understand" in the first speech bubble, to indicate that the thought/sentence is continuing past that panel. It sorta reads like Kotone also paused in the middle of her bit of dialogue if you use a comma, where as a double em-dash would (I think) be used if it were all one "breath" of dialogue from her, but split across multiple panels. So that comes down to whatever the author intended, I guess.