Comments on the pixiv page are nice.

…大ちゃん、ありがとう。
バカなあたいに、いつも付き合ってくれて本当にありがとう。でもやっぱり駄目だね…一緒にはいられないね…。

I'm too unsure of the second line to try translating it.

precia said:
Comments on the pixiv page are nice.
…大ちゃん、ありがとう。
バカなあたいに、いつも付き合ってくれて本当にありがとう。でもやっぱり駄目だね…一緒にはいられないね…。

"...Dai-chan, thank you.
I'm really thankful for you keeping my stupid self company. But it's still no good... We can't both be entered together..."

Not sure what they're being "entered" into. Hisoutensoku, maybe?

It might be "一緒に は いられない ね" instead of "一緒に はいられない ね". So that'd be "we can't be together".

"I was never really on your side."

The fuck?

I see tears,
I see tears are green, red roses too.

Yandere?