>>117345584She was originally created to be a eventual love interest to Bruce/Batman in the Adam West Batman show. (The show writers claim that the cancelled season 4 would have had her and Bruce begin a romance. With her moving into Wayne manor at the end of the season.)
When introduced in the comics, they kept this angle for a bit. She would eavesdrop on her Dad and Batman having conversations and began crushing on Bats. (This is where Timm gets his desire to pair the 2 together.)
Not that long after her introduction happened, she kissed Robin to distract him and it proved popular among the fandom. She was intentionally deaged after the Crisis to make her a similar age to Dick around this point.
The problem is that the whole Titans thing happened around the same time. Dick became Nightwing and started sleeping with Starfire pretty quickly around the same time. So the original plan of coupling the 2 didn't happen.