Meaning of yì xìng:
异性
the opposite sex; of the opposite sex; heterosexual
Tā hé yìxìng de yǒuyì fēicháng chúncuì.
他和异性的友谊非常纯粹。
His friendship with the opposite sex is very pure.
Tā hěn shàncháng yǔ yìxìng jiāoliú.
他很擅长与异性交流。
He is very good at communicating with the opposite sex.
Tāmen duìdài yìxìng de tàidù hěn kāifàng.
他们对待异性的态度很开放。
They have an open attitude towards the opposite sex.
different in nature
Wǒ kěyǐ hé rènhé yìxìng yúkuài de xiāngchǔ.
我可以和任何异性愉快地相处。
I can get along with any person of the opposite gender.