Yes restitution is neccesary to complete your repentance so that ur quit can be taken away. If u re familiar wth d story of zaccheus he told Jesus all I have taken unlawfully I restore sevenfold.this an example of restitution.
Secondly if u dnt do it, u can't find d boldness to talk to her abt Christ n if she finds out later DAT u did all DAT to her, she will take u as an hypocrite