Based on the clues, we can infer that he's lying.
What clues?
"Gulps", "Scratches his head" and "looks from side to side nervously"
If he looks from side to side, we can infer that he can't really dance; if he was able to dance, he would be confident and would have danced with Gina.
If someone looks from side to side, that person is definitely lying because that person is really nervous.
And here's a clue:
"looks from side to side nervously"
Aha! So that tells us that Kareem was lying.
Hope it helps!