Does そうなる have a meaning besides "become so" when used in this sorta context?
Speaker A:あなた、それに興味ある?
Speaker B: うん...まあ、そうなるかな
It looks to me like it doesn't mean "become so", but something more like "I wonder if it's so". Is that wrong?
That なる is difficult.
The original sentence, そうなるかな, is equivalent to (これは)そういうことになるかな。, (これは)そういう話になるかな。 or (これは)興味あることになるかな。.
なる has a meaning like evaluation. For example, 盗まれた紙幣は30億円になる。 does not mean "The stolen bills become 3 billion yen." but "The stolen bills are evaluated as 3 billion yen."
The direct translation should be like "This whole situation may indicate (or be evaluated as a story) that I am interested in it."