How does どうなったら work here?


好きになるってどんな感じ?

どうなったらその人を好きだと判別するの

It's not どうやったら. In the first sentence he asks "How does it fell to fall in
love" but what about second one?




Broadly speaking, どうやったら and どうなったら are both interrogatives for the
cause/reason/condition of something. But やる means "to do", and なる means "(for
a situation) to turn out; to end up". Therefore, どうやったら assumes the cause is
someone's action ("how can you ～", "by doing what"), whereas どうなったら assumes
the cause is a natural phenomenon or an objective condition ("under what
condition ～").

  * どうやったら燃えるんだろう？  
How can we get it to burn?  
What do I need to do to make it burn?

  * どうなったら燃えるんだろう？  
Under what conditions will it burn?  
What has to happen for it to burn?

> どうなったらその人を好きだと判別するの？  
>  Under what conditions can I determine that I like that person?

どうやったらその人を好きだと判別するの ("How can I make it judge?") sounds like there is a
special method just for starting judging, but that's not natural.

