What is this use of と辛い


In the sentence

> 友人に彼女ができると辛い

I'm a bit unclear as to what と辛い is actually supposed to mean (or even if it's
supposed to separately be と and 辛い).

As far as my understanding goes:

彼女ができる means something like "become (someone's) girlfriend"

辛い in this context, I think, means "painful"/"bitter"

So perhaps "(someone) was hurt by becoming girlfriend to friend" (in other
words, they broke up?) What's the use of と辛い here?




This looks to me like a case of the conditional と, basically meaning
'if/when'. The sentence then breaks down like this:

> [[友人に彼女ができると]辛い]

You've got 彼女ができる a bit wrong - it's not 'become a girlfriend' but rather 'get
a girlfriend'. You have to figure out what 友人に is doing here, also. The
'[someone] gets a girlfriend' doesn't have a marked subject or agent in
English, but it has a subject in Japanese that isn't the agent, so the agent
(in this case 'a friend') is added with に. So 友人に彼女ができる is 'a friend gets a
girlfriend', and 友人に彼女ができると is then 'when a friend gets a girlfriend'. The
whole sentence then works out to something like 'it's tough when your friend
gets a girlfriend'.




You know what 辛【つら】い means in this context, but the interpretation of the
first half of the sentence is not correct. "友人に彼女ができる" means "a friend gets a
girlfriend".

  * 友人が彼女になる My friend become a girlfriend (of me, or someone else)
  * 彼女から友人に戻る Become from a girlfriend to just a friend (break up)

This sentence, as a whole, means "It's a painful thing that my friend gets a
girlfriend". The speaker is saying this out of jealousy.

