这茶喝起来有点苦涩。

Zhè chá hē qǐlái yǒudiǎn kǔsè.

This tea tastes a bit bitter.

她微笑着说话，但带着苦涩。

Tā wēixiào zhe shuōhuà, dàn dàizhe kǔsè.

She spoke with a smile but with a hint of bitterness.

失败后，他心中充满了苦涩。

Shībài hòu, tā xīnzhōng chōngmǎnle kǔsè.

After the failure, his heart was filled with bitterness.