I've been studying 中文 for a couple years and one phrase I've learned very recently is this:

我为你感到高兴

(Wǒ wèi nǐ gǎndào gāoxìng)

When somebody for example gets a promotion or graduates from school this'd be something you say, it's a very native Mandarin speaker's way of saying that they feel immensely happy for you.