Kimi no Sekai Kara Watashi ga Kiete mo.
君の世界からわたしが消えても。
The narrator expresses a willingness to act deceptively if it means seeing the person they care about happy. They accept being a substitute in that person's life, as long as they can remain close. The narrator believes that, having lost everything, their presence is enough of a reason to stay—this was their intended path.