What 甜 means
Sweet, literally or figuratively. The written character pairs 舌 (“tongue”) with 甘 (“sweet”). Its older variant 甛 reverses those parts but means the same. Shuowen Jiezi, a Han dynasty dictionary compiled around 100 CE, records 甛; it also appears in an inscription on a Northern Wei tomb dated 521. These attestations show use, not an origin date.
Warm for taste or affection; context shapes the tone.
甜言蜜语 can be flattery meant to persuade.
Combination ideas
3Questions people ask
1Why does 甜 show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type 甜
甜\751CCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.

