Romantic love in literary works: believable or contrived, how authors succeed in justifying its genesis—or get away without.

How authors render blooming love between characters, more specifically, how do they make it believable to emerge?

This question is a new exploration I started after a comment brought up how little we get to understand why Yvonne and the Consul fell in love with each other, in Lowry’s Under the Volcano.

We do get a bit of their mutual history: We witness the remnants of their affection with little gestures (hands meeting, holding; glances), with persistent thoughts and dreams of rebooting themselves in a relationship, or with the fated obliteration of such dreams by the Consul for reasons too long to account here.

But all those details are only showing us their feelings. They depict the result of them being in love. Such clues don’t explain why, and I (and the redditor who pointed this out) find it hard to believe that Yvonne fell in love and still loves this man, the Consul, given who he is and what he became.

This is still a great achievement for a writer to depict genuine love, the result of two compatible people meeting and getting along romantically, but this isn’t what I’m looking for. I’m not sure if I’m explaining it well.

(Quick disclaimer before diving in: for me it’s a complex topic to write on, please forgive my shortcomings in English and that, this time, I got a bit of help for a tenth of the post.)

So, first, let’s review what we have in literature, a rough sample showing the love sentiment and its genesis.

• In Pride and Prejudice, Jane Austen shows how the relationship between Elisabeth and Mr. Darcy blooms with shared glances, subtle physical proximity, admiration, unspoken tension. None of this really tells us why it works between them. The depicting can be convincing and maybe the reader can relate to other cases and infer what makes this work.
• In Romeo and Juliet the tension between the families adds to the passion, making their love forbidden and more urgent—that’s a good catalyst.
• In the Great Gatsby, we have a good clue with Gatsby’s idealization of Daisy, which is a valid reason in my eyes, but this is an illusion. Daisy aloofness is a trait that creates a unique dynamic and I can see how it could help bring them together (not saying this is enough for a successful match).
• In Atonement, by McEwan, the bond emerges from their vulnerabilities, confessions, shared experiences of loss, a whole set which brings genuine ingredients that deepen the connection.
• I never questioned the credibility of Heathcliff and Catherine’s love in Wuthering Heights. A strange and destructive one, but I felt its genesis was well crafted. Could you help me pinpoint how it is done? I would say with a blend of forced circumstances and decisive character traits like stubbornness.
• Anna Karenina (not read yet, alas) seems to make use of shared objects and repeated phrases, to amplify the resonance between the two.
• Jane Eyre has Jane’s internal monologue as a window opened on her growing feeling, longing and desire.

I need to stop the sampling, and I’ll use it as a feed for the argument.

So far we have either:

• Valid reasons that are one-sided, in a sense (like delusions, admiration).
• ‘Reasons’ that can’t hold the comparison with a friendship case. I mean that, for example, sharing a lot of experiences also leads to friendship, not necessarily romantic love. Then, such event or trait aren’t specific and don’t explain why love in the case we're looking into.
• Great depictions of the result of attraction, the manifestation of love, which again don’t explain why it emerged for those two lovebirds, but maybe the reader is first convinced by what’s happening (the bond is there) and then unconsciously make up a rationale to admit it, or maybe it’s a variant of a (guided) suspension of disbelief.

Other possibility: I’m sorry I don’t have an example handy—maybe it’s pervasive in other works still in my blind spot—but I wish I could mention the case of a story just stating the two lovebirds are soulmates, kindred spirits in a romantic way. This is both an easy (contrived?) device, and an acknowledgement of what happens in reality where the mystery of the chemistry runs deep, once we look beyond the mere boxes that are ticked like in a classic match-making test (same social level, good income from one, good looking for the other, shared humor, same level of etc). Those ticks can only ‘secure’, at most, an ‘okay’ relationship which could just as well be friendship with nothing romantic (maybe leave out the good-looking part). I wouldn’t mind if the author simply refers to this mystery as the core justification of why the two click (get together). Of course, this wouldn’t exonerate the author from providing a believable bonding development and an accurate depiction of the feelings themselves, like in the examples above.

And again, maybe the good depiction of the feelings makes the reader unconsciously deduce this kind of generic and mysterious reason for the bond, which is a valid approach as long as it works for the reader.

Lastly, I’m not dismissing the influence of biology and pheromones, but I didn’t find any literary interest in that (nor do I have any example in mind—I would have found it hilarious), so I just left those possible reasons aside.

My questions:

1. Do you remember a well-known piece of literature with two people falling in love and you thinking to yourself ‘uh... I’m not buying it’?
2. In the other case, if you felt that it all comes together in place for romance, what reasons did you get from the authors (masters) for feelings and attraction to become specifically romantic? Whether it was told, shown, or just implied and left to the reader.
3. (For fun:) Conversely, is there a successful work where romantic love in itself is debunked as an overblown folklore, a complete scam? I feel there’s potential here, so it must have been written.
4. Overall, does my main question make sense to you? (I mean this exploration)

Thank you!

(Disclaimer #2: Not trying to look like something—my non-native English might seem formal or odd at times. Thanks for bearing with me, as I’m an amateur)