Match made in heaven 天作之合
= A relationship that is likely to be happy and successful
double date 雙對情侶約會
= A date which involves two couples
= Making an excessive display of affection
On the rocks 兩個人的關係觸礁
= A relationship experiencing problems
I think their marriage is on the rocks.
Love rat 花心、濫交的愛情騙子，負心漢
= Somebody who has an affair while in a relationship
Puppy love 年輕人之間不成熟的愛，沒有那麼認真的進入關係
= Temporary infatuation between young people
Nowadays puppy love is not rare among middle school students.
Head over heels 對某人神魂顛倒
= To be very much in love with someone
Tom was soon head over heels in love with her.
Have the hots 深深著迷
= To be strongly attracted to someone
He's got the hots for that lovely girl.
hit it off 兩個人初見彼此時，就馬上天雷勾動地火喜歡上對方
= to be friendly with each other immediately
Mary and Tom met at a party last week and hit it off.
pop the question 向某人求婚
= to ask someone to mary you
" Love makes the world go round. "