My only thought was hanging a lampshade on it like: "If this was a story, thought Alice, maybe they had a chance of getting together. But
this is real life so she wasn't getting her hopes up."
But I sort feel that that is quite conspicuous and might even be what
a romance would do.
I agree, the lampshade is so conspicuous that drawing attention to the failed relationship is 'promising' the opposite. I think a better idea is to signal the truth to the reader while the character remains in denial.
In a traditional romantic plot, the characters resist until the relationship feels inevitable. In Pride and Prejudice Elizabeth is so vocally opposed to Darcy – not just as a husband but as a human being – the final joke of the novel is when they finally get engaged her family feels sorry for her.
Reversing on that logic, a character convinced of her relationship while the story signals 'no', should promise the reader a disillusionment or backlash when her fantasy comes crashing down.
I offer a list of 'red flags' that signal a doomed relationship. Some are contradictory, some impose on characterization. Some are tropes, and some are based on rl.
Alice is unworthy
(assuming a sympathetic, deluded Alice):
- Alice is inexperienced and naive about men.
- Her relationship ideal is inconsistent, or based on dysfunctional role models.
- She changes herself to win his approval.
- She increasingly excuses Villain's flaws to preserve a fantasy.
- She chooses Villain over her friends, sabotaging her own support network.
- She sees others as a threat to her status with Villain.
- She steals/lies/frames someone for murder to help Villain.
- She has self-serving motives for the relationship (money, power, family name)
- She wasn't interested in him, until her friend starting dating him.
- She can't be happy seeing him with someone else.
- She is already insecure, and the relationship makes it worse.
- She is entitled, and assumes the relationship is requited.
- She lies to imply there is more relationship than there is.
- She does too much.
Readers should be thinking "Oh. that poor dumb girl."
Villain is unworthy
(foreshadowing his villainy without kicking dogs, etc)
- Villain is a creep who pushes boundaries (yeah, I see where this could signal a 'romance trope' where she 'fixes' him).
- He has self-serving motives for the relationship (money, power, family name)
- He only noticed Alice after discovering she could lead to an opportunity.
- He imposes tangible loses on Alice (financial, work opportunity, reputation).
- He pursues Alice and the other POV character simultaneously with the same technique.
- He has sex with people he doesn't care about, and breaks up if they become attached.
- He does not value relationships, but assumes everyone else does (the suckers).
- He attacks an enemy through their marriage/love interest.
- His status requires him being a free agent, or he does not want public displays of affection.
- He needs a status marriage.
- He thinks love is a vulnerability, but sex is a prerequisite.
- He has relatives who control his future, and ultimately he values his class, wealth, status more than love.
- He is over-invested in the 'romance' preferring the chase to the conquest.
- He keeps his clothes on during sex (symbolically hiding himself)
- A fundamental political or religious hypocrisy (vow of chastity, ethnic supremacy)
- He judges her body-type, skin color, or other aesthetics in relation to his future children.
- He's using Alice as a beard to misdirect from another relationship.
- He's a different person when they are alone, not in a good way.
- He doesn't do enough.
Any 'bad boyfriend' trope will work, but also non-romantic situations where he prioritizes himself and his status over others.
The relationship is cursed
(assuming a no-fault, doomed relationship)
- In a love triangle someone is 2nd choice. Zero-sum game means one woman will ultimately be the odd-man out. (Rivalry is a big Romance Genre trope, so the goal is to signal it was never an even competition.)
- Their beliefs/values are incompatible. Disagreements threaten their friendship, arguments result in tears, not make-up sex.
- One is much more experienced/worldly than the other.
- They are both the same 'type' and compete for status/attention/jobs.
- The sex is cruel, selfish, one-sided.
- The sex is awkward, an 'intimacy embarrassment' is handled badly.
- The sex is intoxicating and increasingly risky (both are using the other to work through past issues.)
- They have conflicting priorities, which didn't matter... until it mattered.
- They have incompatible sexual orientations (she wants a daddy, he wants a stripper), or they cannot provide what the other needs (stability, excitement, submission, spirituality, etc).
- Society would never accept them, and it sours their time together.
- There was never a relationship, just presumption or family obligation.
- They do not have the maturity to work through hurdles together.
It might be interesting to point readers to feel sympathy towards a 'no fault' breakup, before Villain evolves into a complete bastard, or before we realize Alice is a biased narrator.