分かんないんだけど

I don't understand, though

→ 分かる
phrase Uncommon #15,718
I don't understand, though An informal contraction of 分からないんだけど. Often softens a statement or introduces a question, with the final んだけど sometimes left trailing: “I don't understand...” or “I don't know...”
JA: この問題の答えが分かんないんだけど、教えてくれる?
EN: I don't understand the answer to this problem—can you explain it to me?

どのバスに乗ればいいか分かんないんだけど

I don't know which bus I should take.

何が言いたいのかさっぱり分かんないんだけど

I have absolutely no idea what you're trying to say.

何が悪いのか分かんないんだけど

I don't know what's wrong, though.

何が言いたいのか分かんないんだけど

I don't know what you're trying to say.

意味が分かんないんだけど

I don't understand what it means.