Why can't all romance manga be this smooth with confessions? No misunderstandings. No lying. No third wheel love triangles. No shyness that causes you to not confess for 90+ chapters. No "Does she like me? Do I like her? Does he like me? Do I like him?" Just simple clear communication of feelings: "I like you." "Guess what? I like you too!"
Feels really really good.
Wow, must be one of the smoothest confessions I’ve read in a manga, NICE
I mean, it's definitely more likely with side-characters than main characters, for sure. Like take The Girl I Like Forgot Her Glasses, where the first overt couple in the story is Asuka Kawato and Tomo Yasaka, which technically paved the way for Ai Mie to understand what it looked like when a person liked someone else in a 'special' way and then realize Kaede Komura liked her, so she knew her feelings were reciprocated long before the confession proper.
But I personally don't think we should stress too much about how long shit takes. Sure, HoriMiya had one of the faster main couple relationship starts, at least in terms of percentage of the chapters are pre-relationship vs relationship, but on average I feel like most main characters in manga and anime don't have their shit together enough, especially as teenagers, to sort out their feelings sufficiently and have the confidence. A lot of them seem to have emotional and maybe mental baggage due to upbringing or past school situations, or both, that make them far too uncertain to be anywhere near this decisive in love, and I don't blame them- shit can be nerve wracking.
I feel like getting bent out of shape over something that's pretty common in the genre would just cause oneself unnecessary grief. Just appreciate when it actually does go smoothly and swiftly and leave it at that. (Edit: Not specifically saying this in response to you two, by the way, just expressing a bit of exasperation about this sort of sentiment in the comments for the stories I've been reading of late)
I will note... Two examples of extremely smooth 'meeting to relationship start' that I've seen in my anime/manga binging of late are stories where the main genre is more of a supernatural mystery vibe, so it's not like the relationship is a main focus, but it does get decent attention as a thing that's established and ongoing while mysteries are solved: Rascal Does Not Dream and Bakemonogatari. There's also ToniKawa, but I feel like that's a special case where they literally jump from confession to marriage proposal (or should I say counter-proposal?) right away, since that's literally the premise of that adorable story.