All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
As long as a woman is marriageable to a man, he is not permitted to deal with her except within the religious limits. Therefore, it is not permissible for a man to say expressions of love and the like, as this is a means that could lead to the evil fornication (or adultery).
As regards informing her with your intention to delay marriage for this long period, then there is no harm provided the religious requirements are observed, like not being in seclusion with her and the like.
Furthermore, it is not permissible to talk to her in order to get to know her. This could be achieved by asking trustworthy people who know her; rather this is a better way of knowing her and getting a more accurate information.
Allaah Knows best.