Here's what happened in that episode:
* Terra joins the Teen Titans, but her true intentions are to betray them.
* She manipulates Beast Boy's feelings for her, using him as a pawn in her plan.
* In the end, Terra betrays the Titans and joins Slade.
* Beast Boy is deeply hurt by her betrayal.
While there is a strong emotional connection between them, there is no romantic interaction or kiss in "Titan Rising."
It's important to note that the Teen Titans animated series, while based on the DC Comics characters, takes some creative liberties with the storylines and relationships.