XばYのに
expresses the speaker’s regret that X is not the case, because if X were realized, it would be Y (the desired result).
Xばいいのに
is a common set phrase used to express such regret when the speaker feels X is not and will not be realized
~なあ
is often used when expressing the speaker’s wish
When Y is in past tense,
it expresses the speaker’s regret that Y (the desired result) would have happened if X had been true, or the speaker would have done Y if X had been true
もうちょっと早く来れば、大好きなアイドルが見えるのに。
If only I came a little earlier, I could have seen my favorite idol.
このかばん、欲しいけど高いなあ。もっと安ければいいのに。
I want this bag, but it's pretty expensive.. If only it were a bit cheaper..
日本語がもっと上手なら、仕事が見つけれるのになあ。
If only I were better at Japanese, I would be able to find a job..
映画はとても面白かった。君も行けばよかったのに。
The movie was very interesting. You should have come!
車で行けば、間に合ったのに、自転車に乗ったから遅れてしまった。
I would have made it on time if I came by car, but I came by bicycle and was late..
もうちょっと早く連絡してくれれば、迎えに行ったのに。
I would have come to pick you up if you contacted me a little sooner.
アパートがもう少し学校から近ければ、便利なのに。
My apartment would be much more convenient if only it were a little bit closer to school.
犬アレルギーさえなければ、家で犬が飼えるのに。
If only I didn't have a dog allergy, we could have a dog at our house.
あと10分があれば、全部の問題を解くことができるのに。
I would have solved every problem if only I had 10 more minutes.
昨日のパーティーすごく楽しかったよ。トムさんも来ればよかったのに。
Yesterday’s party was fun. Tom should have came.
あの時、「好き」って言えばよかったのに、どうして言わなかったんだろう。
I should have said “I like you” then, so why didn’t I?
もう少し安すければ買うのに。
If it was a little cheaper I would buy it
宿題やテストがなければ、勉強は楽しいのに。
If I didn’t have homework or tests, studying would be fun
もう少し優しく接してくれれば、いい先生なのに。いつも怒ってばかりで、ストレスだ。
If they treated me more kindly, they would be a good teacher. They are always stressed and angry.
隣のクラスの先生、すごく美人だよな。俺らのクラスの先生ならいいのになあ。
The neighboring class’ teacher is a beautiful person. It would be nice if they were my class’ teacher.