翻译成英文：从前，我认为两个人在一起就会快乐，不在一起就会悲伤的情感表现就是爱情

Once upon a time, I think two people together will be happy, not together will feeling of sadness performance is love

高兴：happy ,glad ,pleased,pleasant,excited / exciting ,amazing/amazed,thrilled,suprised,terrific,wonderful ,lucky,

悲伤：sorrowful ,sad,miserable（悲剧的）,tragic,unhappy ,

郁闷：blue,upset ,embarrassed(尴尬的) ,depressed ,frustrated,worried,puzzled

The more painful,the happier

The more you treasure,the more you are afraid of losing

The happier,the sadder