Edit: Many readers seem to have forgotten that in a flashback, Natsumi already had a high school crush that she wanted to give Honmei Choco to but never did which was why she said what she did this chapter.
That was #57.5.
I see some ambiguity that lends to the theory that some are making here-- specifically, what she's saying can come off as a cover-up, especially since we don't ever see the guy in question and there's no weight in her explaining her failure to gift this guy true-feeling chocolate, yet she has a focus panel on her lower face (as to conceal her eyes) after Futaba goes on her consoling tirade about how the chocolate Natsumi gave her is friend chocolate, and the last panel for the chapter (a pan up to capture Natsumi's whole face)
almost looks like her trying to blink away tears while smiling, as if she's ironically disappointed by Futaba's heartfelt consolation/motivation.
...but then, she could alternatively be moved by Futaba's genuine gesture, and she could have actually tried giving that chocolate to a guy. But then, how would
she have failed, when she's so cool? Was she
too cool? The mechanisms of Natsumi's love life are an enigma-- all we know is that she was willing to immediately break up with a guy over him saying that he went out with her because her breasts were bigger than his previous girlfriend's.
Her being wistful in regards to thinking of Futaba and Takeda seems like it's only a recent thing, though-- closer to the beginning of her appearances, she just straightforwardly teased Futaba about it and gave her advice with not even the slightest hint of a reservation. This wistfulness we're talking about looks like it developed gradually or is generally repressed, but its revelation seemingly coincides much more with her stating what her agony is about: the distance between her and her once super best friend is growing as they grow older. They're doing less things with each other. Futaba eventually being in a relationship with Takeda is relevant to that insecurity inasmuch as such a relationship has the potential of widening the aforementioned distance, and (here's me speculating) it serves as a contrast to her life: monotonous, nabbing a high school boy with the same cuteness index as her best friend off the street so she can watch movies with him in her apartment she's thitherto only brought her best friend into. And does she even
have friends other than Futaba, Futaba's workmates, and Yuuto? I can't recall them, which may just be a function of how thoughtful this manga was meant to be--
that is to say, I'm writing all this about a late Heisei era slice-of-life rom-com that's absolutely going to end with the male lead splitting the female lead in half with his gorilla cock, where the cast is small and characters pop in and out almost strictly for making a specific scenario. I am thinking far too much about this.
Still, there could also be a point in this set-up: she lives a fairly isolated existence apart from her only friend (if she indeed is), who-- even though she wants her to find happiness-- is progressively drifting away from her just because they're growing old. Rather than her sticking to Futaba because Futaba needed her, it was "ironically" the other way around (if you've played Persona 4, Chie and Yukiko's relationship-- also that of best friends-- at least rhymes with this... and incidentally, a minority also perceived homoromantic undertones in that).
At any rate, I'm wary because I've been pied piper'd before with people doing things like finding obscure "hints" in a vocal track for an anime in order to mine support for their ship (and they were so convincing about it, at least I thought at the time). No clear intentionality on the part of the writer, combined with an
active interest in a perceived ship, is a combination I don't have faith in-- I still remember how, in the late aughts/early-teens, weebs tried to make out Kagami Hiiragi as wanting to have sex with Konata because they started out from their interest in that ship and then attempted to reconstruct a line she says in an OVA ("koi o shitai", or, "I want to fall in love"-- she was waking up from a dream where she was a magical girl IIRC) as "I wanna fuck with Konata" as if they knew Japanese. They even thought an SFX was a censor because they somehow thought that Japanese censorship guidelines were anything like American ones. I've also seen the
inverse happen, where weebs deny any level of reciprocal interest between two characters
even when outright rom-com/rom-drama clichés (direct or otherwise)
are used to drive the point home.
Then we look back at chapter 121. Not much here, except that Natsumi has her fingernails painted yellow, like usual. Except one is painted green, like Futaba's hair. Her left. ring. finger.
Yes, and the curtains were blue. You're undermining a thesis that may have merit when you feel you have to microscopically focus on something vague in its own right.
When I think of Futaba liking Takeda, I don't at all think about how her hair and scrunchie are the same EVA-01 colors as the tie Takeda wears-- because I don't have to. In the face of the fact that she clearly has interest in him, it's such an irrelevant detail that isn't even anchored in the intentions of the characters. It even has a significant chance of being arbitrary or coincidental.
Also the tags on the latest pixiv post are pretty indicative. "想いをひた隠しにする親友の話" Like, COME ON. My best attempt at a smooth translation of this is "A story about hiding your feelings from your best friend at all costs".
想いを
ひた隠しにする (roughly, "to make concealed (one's) (romantic) thoughts at all costs",
see here for usage of A を B にする) is, here, an
adjectival clause that modifies 親友 ("close friend").
That is, the title is "a story of a close friend who makes their feelings hidden desperately"-- or a bit less literally, "a story about a close friend who desperately hides their feelings".
If "the latest pixiv post" was this very installment, this could be about Natsumi. It could refer to the two of them. It's absolutely relevant, at the least, to Futaba, who finds it easier to plot to seduce Takeda than to "just" tell him she likes him. She's arguably the only one desperate about anything-- much less concealing feelings.
There are other ones like 「早く告れば良い後輩の話」which I don't really have the expertise to translate properly (hayaku kokurebaii [or kokurebayoi, but probably the former], the 告れば良い gives me trouble. 告れば is the hypothetical form of a slang for "confess (love)", but ~ば良い can mean different things than just "if".
~ば良い ("~ba-i-i", or "~ba-yo-i"-- they're equivalent) doesn't mean "if"-- it's a
construction that follows from the hypothetical stem form of a verb (in this case, 告れ, or "koku-re") to create the sense of "should" or "it would be good if...".
...for the record, the title is "a story of a kou-hai (後輩) who should confess quickly".