Complex sentence: Seeing how clingy he is she assumes he is acting this way to just mess around with her and scare her possibly knowing her true identity however soon after he buys her an expensive purse at which she realises that ths is not a prank.
Split into simpler sentences: Seeing how clingy he is she assumes he is acting this way to just mess around with her and scare her possibly knowing her true identity. However, soon after he buys her an expensive purse at which she realises that ths is not a prank.