You make my head spin.
mi FAI ji-RA-re la TES-ta — stress on 'fai', 'ra-', 'tes-'. 'Girare' has three syllables: ji-RA-re.
Expressing that someone has a dizzying, intoxicating effect on you — romantic and slightly theatrical in the best Italian sense.
'Mi fai' = you make me. 'Girare la testa' = to spin one's head — an idiom for being infatuated or overwhelmed. 'Girare' means to turn/spin. The phrase implies pleasurable disorientation caused by attraction.
Quando sei vicino/a a me non riesco a pensare chiaramente.
When you're close to me I can't think clearly.
More explicit about the physical proximity effect — intimate
Mi togli il respiro.
You take my breath away.
Breathtaking — 'togliere il respiro' is a vivid Italian romantic idiom
Non so cosa mi fai.
I don't know what you do to me.
Vague and mysterious — leaves the effect unnamed, which can be more powerful
Italian flirting is often theatrical and expressive — grand statements are expected and appreciated. Saying 'mi fai girare la testa' is not considered excessive; it is considered passionate and sincere. Italian romantic culture rewards emotional expressiveness.