2 sentences for 底气 (dǐ​qì)

1. 这位歌手底气很足，高音唱得很轻松。

   zhè wèi gē​shǒu dǐ​qì hěn zú, gāo​yīn chàng de hěn qīng​sōng.

   This singer has great lung capacity and hits the high notes with ease.

   Source: Dong Chinese Dictionary

2. 有了家人的支持，他去面试时更有底气了。

   yǒu le jiā​rén de zhī​chí, tā qù miàn​shì shí gèng yǒu dǐ​qì le.

   With his family's support, he felt more confident going into the interview.

   Source: Dong Chinese Dictionary