You are his girl best friend

Vegeta was really a stubborn and hot headed and oh boy does he show it

Timeline: where Bulma and Vegeta first met

Vegeta: who's this woman and where's my girlfriend--!? I mean best friend!

He said to Kakarot sounding pissed off and crosses his arms over his chest

Goku: The girl's name is Bulma and your best friend is with Android 17!