[Kitkatbanana]

So I'm looking for a song but I don't know how to find it. It is of course Japanese, sung by a female singer (I think her name begins with either a Y of F, I can't remember but I'm 70% sure it's F). One of the only pictures I remember seeing of her was her in a pink/white dress standing in front of a background that has cherry blossoms (I think this might've been an album cover). There's a particular song by this artist that I'm searching for but I can't remember any words apart from "yureru", which I know LOADS of Japanese songs contain. The song was quite slow, had a piano(/violin?) in the background and was quite peaceful.

If it helps any the first time I heard this song was years ago (about 2013/14) on a walkthrough of Love Letter From Thief X (I think Hiro's path or maybe a prologue) which has since been deleted from YouTube. If anyone knows the video which I'm talking about, do they remember the name of the song?

I know this is insufficient information to go off of and I described it very badly, but it's been years since I've ever heard this song.