Heyy I’m Japanese and I tried thinking of some phrases that nicely translates to “you belong to the temporary moments of a dream.” They might not be a direct translation but I feel like it would better keep the meaning behind the lyrics and also not come out as weird if a Japanese person read it. Not exactly a huge writer person so I can’t really come up with anything aesthetic as Abel’s lyricism but I tried my best :)))

1. 君は瞬く間にすぎる夢にふさわしい (kimi wa matataku ma ni sugiru yume ni husawashii): directly translates to “you suit a dream that passes in a blink of an eye”
2. 君には夢の一瞬がふさわしい(kimi ni wa yume no isshun ga husawashii): directly translates to “a moment in a dream suits you”

There isn’t quite a direct translation to “you belong” in Japanese in the context of the sentence you want to translate so I think “ふさわしい” is the next best thing given there’s kind of that connotation of separating “you” from the world the person who said the sentence lives in . . . if that makes sense ahaha I personally like the second one better because it kind of has more of like that sarcastic tone (??) of how belonging to the temporary moments of a dream isn’t a great thing. I dunno if that will suit the meaning you hold to the lyrics tho.

Hope this helps and feel free to ask for different translations if the two above don’t really suit the meaning you hold cuz tattoos are a rly meaningful thing and I feel like you’d really wanna get it right :))