Most English speakers would naturally think that a word like "haenyeo" should be pronounced as "haen-yeo", but in fact it should be "hae-nyeo" (해 녀).
This would also affect what the expected hangul representation is.
What rule determines where the break occurs?
Converting from Hangul to Alphabet is a lossy process, so (in many cases) you cannot know the original Hangul spelling for certain. In your example, if we had a hypothetical word "핸여", it would also become "haenyeo".
In a sense, to reverse the conversion, you have to already know that 해녀 is a word but 핸여 isn't.
