which "that" to use?

[Torukä Nari]

Srung! This is my first attempt at an actual full sentence, and I'm kinda stuck for which "that" to use.

Nì'aw 'u tsnì 'erì'awn wong li tìlatem. Attemped mean is (the) Only thing that stays the same in change. But I don't know.

[Tsamsiyu92]

tsni is more like "thus..." or "so..."

In your case it's a relative clause (that/which/who/... in english), which need a "a".

Example: Tute a kawng lu. (Person that is evil).

Or in your case:
Nì'aw 'u a 'erì'awn wong li tìlatem.

[Torukä Nari]

Ok, thanks. I was kinda confused.