The sources checked record bestie only as a word, not as a personal name.
Friend
Cute
Gold, Brown, Black
Any Size
Unisex
English
B
6 Letters
An English surname
Diminutive of Bill; also a feminine form of William
Variant of Bobby; as a feminine name a diminutive of Roberta or Barbara
Recorded as a masculine given name in English
A nickname, recorded as borne by several men
