Θέλω να συναντηθούμε ιδιαιτέρως.
or κατ' ιδίαν, for hardcore fans of stiff (or stilted) language style
Εdit:
προσωπικά actually means "in person" (αυτοπροσώπως) or "personally" although it usually implies "privately"
while ιδιαιτέρως means "privately" i.e. with nobody else present.