にわか（俄）には＝immediately, at once, of a sudden

Correct.

You've got it.

Awesome; thanks, you two. =D I'm glad I was at least on the right track with the listening, haha. And Supperman, that's no problem now that I know what it is; I figure "Geez, he's just so lovestruck..." should do the trick. :)

Just a shot without any context...

If it didn't fit the context, it was probably because you translated it with the first-person as the subject, no?

Try and see if "It sounded far-fetched at first." still wouldn't fit there.

Hi, I can across this phrase "オレンジ・ジュースが入ったグラスにストローを挿す (put a straw into a glass of orange juice)", I was wondering if "置く" could supersede "挿す" as "Put" in the above phrase?

こたえます - Answer, Reply, Respond.
返事します - Answer, Reply.

I keep messing them up.
These words seem to be really similar. Does anybody know the difference between them?

No, it could not.

If you said ストローを置く, native speakers would automatically think you are placing it someplace and doing so horizontally. You are not using the straw.

Thanks masaegu.

Very tricky question because you are writing the first one in kana. Which こたえる are you referring to? 答える or 応える?

返事する means "to reply" when your name is called or when you receive a letter/email, etc.

答える = to answer a question

応える = to respond, to react, to reward

Ahh sorry, the IME didn't produce the kanji.

I meant to say 答える

Thank you for the answer.