Bolding what you added...

"As they age, they gain an enhanced ability to divine the intentions and character of their partner, and greater emotional stability to deal with unfortunate outcomes, by interacting with peers and adults in friendly, romantic, and erotic ways."

You've complicated matters by modifying what they gain as they age by a specific means that might help then get there.

But if you separate it out to address that concern, I don't think it is at all necessary.

They can also gain those things by reading books, listening to stories that peers and adults tell them, and simply having their brains mature.

I can learn about judging someone's sincerity by interacting with them on a variety of things people can be insincere about, and the knowledge will quite likely transfer to their sincerity about a romantic relationship.