i've read somewhere that romance as a genre isn't the same as romance as in the actions or affections attributed to it.
Romance itself is just a giant genre with tons of content-subgenre which actually define what happens. It's a bit like saying "all action movies". The main genre itself are often defined through the main value that is changing throughout the story.
For romance that would be the relationship between the MC another character ranging somewhere from the negative ("hate") to the positive ("love"). For your typical subgenres without much thinking:
- Courtship (will they/won't they): This would be what we normally think of as "romance".
- Marriage: People need to change because their relationship has to survive hardship
- Erotic: Driven by desire with or without actual feelings.
- Forbidden love Story: Romeo and Juliet
- Compulsion/Obsession: One going after the other without mutual feelings
...
And most of those can - but don't need to - end with a happily ever after.
Courtship can clearly end with "she rejects him", marriage can end with "She leaves him, but he realizes his mistake and changes for the better", forbidden love often ends in tragedy, etc.
Especially for the romance genre it's also often part of multiple genres, where the other genres give the actual reason to change (Your typical "he has to overcome X to realize").
For your teasing, it's often that the main content genre of the story will be action or something else and the romance is just a sub-genre to that plot, which is why they often don't hit all the points of a romantic love story...