I originally thought it was suki (<I> like <you>) as well, but now I'm not so sure.
Obviously there's the ki character キ in katakana,
but the character that's half-shown can't be the su character in katakana since that's ス and it didn't look like that at all.
Maybe she wrote su in hiragana す which matches much better, but I don't know why she would mix hiragana and katakana together like that
Edit: ignore me, I looked at it again and it's definitely a hiragana ki き... I think my brain automatically processed the curve as manga SFX for movement or something