Are you ready?
SEI PRONta — two short words, stress on 'pron-'. The 'ei' in 'sei' sounds like the 'ay' in 'say'.
Said when picking someone up for a date or when you're both about to leave. For a man: 'Sei pronto?'
'Sei' is the second person singular of 'essere' (to be). 'Pronta' is the feminine adjective meaning 'ready'. This is one of the first things said at the start of an outing and sets a light, anticipatory tone.
Possiamo andare?
Shall we go?
Softer and more collaborative — implies you are both deciding together
Ci sei?
Are you there? / You ready?
Very colloquial — used among close friends or when texting before a date
Ti aspetto fuori.
I'll wait for you outside.
Said when arriving early and giving the other person a moment
In Italy, punctuality on a first date is more relaxed than in northern Europe. Arriving five to ten minutes late is common and not considered rude. However, keeping someone waiting more than fifteen minutes without a message is poor form.