Cynthia asked me another question, which is very nice of her considering it took so long to answer the last one.
Quick set up:
We'd been talking about motivation and conflict, and I mentioned the fact that the heroine's conflict is because her motivation to chase the hero is in conflict with her subconscious fear that a relationship with the hero won't come close to the ideal relationship her parents share.
In other words, the heroine has two motivations. Her conscious motivation is to chase the hero and marry him. Her subconscious motivation is to push the hero away because she's afraid a relationship with him won't work.
This is the question:
How would one portray a subconscious fear in a book? It seems this would be not easy/impossible to do. Is it just a matter of how she reacts?
Yes, it is. I'm afraid of snakes, but on the other hand I used to know a lot of people who had snakes as pets. Every time I'd go to their house I'd make sure not to look at the aquariums while I was there, and if we were out together, I'd always be looking at their person or purse (or car) for movement, in case they were carrying their snake with them. Although it's a conscious fear the actions I took are actions that can be used to show a "sub"conscious fear of snakes (if I was too macho to admit my fear and in full suppression mode).
The fact that the house is full of snakes (in aquariums) and the actions the character takes (nervous jumps, trying to keep their eyes on the wall, short glances at stealthy movement) together with the circumstances creates an equation.
circumstances + actions = showing subconscious fear
If you are showing the circumstances and actions taken by the character (in reaction to those circumstances) clearly, the reader will be the one who adds two and two together (which also draws them into the story) and says, "Aha!!! She's afraid of snakes!"
So the heroine would (after interactions with her parents (the circumstances) demonstrating their marriage) be comparing the way they interact with the way she interacts with the hero (the actions). Maybe she can watch her dad present her mother with a little posy he picked while they were walking in the gardens. And notice that hero brought her a can of cookies (something her father never did to her mother), not realizing the hero knows (and loves) her (subconsciously) and is doing it because he wants to make her happy. It's a misunderstanding, but a misunderstanding that shows her fears that even if the hero does come up to scratch, her marriage with him won't be the Eden she dreams about. And it also shows the hero being thoughtful and worthy of love, and his subconscious longing for her. Something she can blow up by rejecting the cookies or gifting them to her maid.
The reader doesn't need to know about the character's subconscious fear or motivation right up front. It's something they'll find out for themselves as the book goes on. You, on the other hand, do need to know what's really going on so you can build in the "circumstances+actions" to show what's really going on in the hero and heroine's minds unbeknownst to them.