Hello~ 너만있으면, "nothing but just you~" 너만 있으면 돼, "All need for me is just you" 너만 있으면 돼 is a sentence. but 너만 있으면 is a part of a sentence. You can say 너만 있으면 돼 to show your mind, but if You say 너만 있으면, people ganna ask you the meaning of it. like saying "so?" However, some particular situations, you can say 너만 있으면, as a full meaning. for example, A: Does any other things you need? B: well... 너만 있으면. ( same meaning, All need for me is just you, in this case) A: Ahh... okay... thanks!

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