3 sentences

1. 他因为中年丧子，性格变得非常消沉。

   tā yīn​wèi zhōng​nián sàng zǐ, xìng​gé biàn de fēi​cháng xiāo​chén.

   Because he lost his son in middle age, he became very despondent.

   Source: Dong Chinese Dictionary

2. 由于连续的挫折，他的情绪十分消沉。

   yóu​yú lián​xù de cuò​zhé, tā de qíng​xù shí​fēn xiāo​chén.

   Due to continuous setbacks, he was feeling very dejected.

   Source: Dong Chinese Dictionary

3. 这种颓废的音乐容易使人的斗志消沉。

   zhè zhǒng tuí​fèi de yīn​yuè róng​yì shǐ rén de dòu​zhì xiāo​chén.

   This kind of decadent music can easily dampen one's morale.

   Source: Dong Chinese Dictionary