2 sentences for 坦 (tǎn — open-hearted)

1. 他为人坦率，从不隐瞒。

   tā wéi​rén tǎn shuài, cóng bù yǐn​mán.

   He is a frank person and never hides anything.

   Source: Dong Chinese Dictionary

2. 只要没做亏心事，他的心里就会很坦。

   zhǐ​yào méi zuò kuī​xīn​shì, tā de xīn​li jiù huì hěn tǎn.

   As long as he hasn't done anything against his conscience, he feels at ease.

   Source: Dong Chinese Dictionary