魚心あれば水心あり

うおこころあればみずこころあり

if you do a favor for somebody, you will get a return favor, if a fish is friendly toward water, water will be kind to the fish too, you scratch my back and I'll scratch yours

あるある

Oh yeah, Of course it is so, Cheer up, that's average, It happens, It's possible, Don't worry, it happens

心当たりがある

こころあたりがある

to have an idea, to have a clue

魚心あれば水心

うおごころあればみずごころ

if you do a favor for somebody, you will get a return favor, if a fish is friendly toward water, water will be kind to the fish too, mutual back-scratching

水心あれば魚心

みずごころあればうおごころ

if you do a favor for somebody, you will get a return favor, if the water is kind to fish, the fish will be friendly toward water too, mutual back-scratching

心する

こころする

to take care, to mind, to be attentive

心得る

こころえる

to know, to understand, to be aware of, to regard as, to take for

あるあるネタ

observational humour; observational comedy

心を配る

こころをくばる

to give attention

心温まる

こころあたたまる

to be heart-warming

心がける

こころがける

to keep in mind, to bear in mind, to try, to aim to do, to endeavor, to endeavour

心に残る

こころにのこる

to stay in one's heart, to be enduringly memorable, to be unforgettable

心休まる

こころやすまる

to feel at ease, to feel relaxed

心が躍る

こころがおどる

to be thrilled, to be excited

心内にあれば色外にあらわる

こころうちにあればいろそとにあらわる

what you believe in your heart is revealed in your face

心

しん こころ

mind, heart, spirit

ある時

あるとき

once (e.g. "once, when I was studying.."), on one occasion, at one point

数ある

かずある

numerous, many

あるに

and yet, even so, however