I love you is “我爱你 （Wǒ ài nǐ）”in Madarin Chinese. The traditional Chinese characters is “我愛你.” Chinese character 我 (Wǒ) radical is 戈, means I and me,  爱”(ài) radical is 爫， means love people or things, 你 (nǐ) radical is 亻, means you. It is mostly used when you are dating a Chinese man or woman.

Chinese character: “我 (Wǒ)”means I and me.
拼音 (pīnyīn) pinyin: wǒ
部首（bù shǒu）radical：戈
笔画 (bĭhuà) number of strokes: 7
笔顺 (bǐshùn) stroke order:

Chinese Character: “爱”(ài) means love
拼音 (pīnyīn) pinyin: ài
部首（bù shǒu）radical：爫
笔画 (bĭhuà) number of strokes: 10
笔顺 (bǐshùn) stroke order:

Chinese Character: 你 (nǐ) means you
拼音 (pīnyīn) pinyin: nǐ
部首（bù shǒu）radical：亻
笔画 (bĭhuà) number of strokes: 7
笔顺 (bǐshùn) stroke order:

For example:
Wǒ ài nǐ! Nǐ kěyǐ zuò wǒ de qīzi mā?
1. 我爱你! 你可以做我的妻子吗？
I love you! Could you be my wife?

Wǒ jīngcháng duì wǒ de érzi shuō, wǒ ài nǐ!
2. 我 经常 对 我的 儿子 说，我爱你！
I often say to my son, I love you!

生词 (shēnɡcí) vocabulary
妻子 (qīzǐ) n. wife
经常（jīngcháng）adv. often,always
儿子（Érzi）n. son