我要你三个字不是四个字
[wŏ yào nĭ sān gè zì bù shì sì gè zì]
Literally 'I love you has three characters not four', this refers to someone being annoyed by another person saying or adding more than just 'I love you' such as including their name in the phrase. In short, it's expressing a feeling that extra terms aren't necessary in expressions of love.