2 sentences for 异性 (yì​xìng — opposite sex)

1. 他在异性面前总是感到很拘束。

   tā zài yì​xìng miàn​qián zǒng​shì gǎn​dào hěn jū​shù.

   He always feels very self-conscious in front of the opposite sex.

   Source: Dong Chinese Dictionary

2. 他最近桃花很旺，吸引了不少异性。

   tā zuì​jìn táo​huā hěn wàng, xī​yǐn le bù​shǎo yì​xìng.

   He's been very lucky in love lately, attracting many members of the opposite sex.

   Source: Dong Chinese Dictionary