我相信你。

Wǒ xiāngxìn nǐ.

I believe you.

我不太相信你，因为你常说谎。

Wǒ bú tài xiāngxìn nǐ, yīnwèi nǐ cháng shuōhuǎng.

I find it hard to believe you, because you often lie.

你要相信自己能做到！

Nǐ yào xiāngxìn zìjǐ néng zuòdào!

You need to trust that you can do it!