Usages of fàngxīn
听到 你 的 声音， 我 就 放心 了。tīngdào nǐ de shēngyīn, wǒ jiù fàngxīn le.
When I heard your voice, I felt relieved.
知道 你 在 家， 我 就 放心 了。zhīdào nǐ zài jiā, wǒ jiù fàngxīn le.
Knowing that you are at home, I feel relieved.
Elon.io is an online learning platform
We have an entire course teaching Chinese grammar and vocabulary.