Well it can have a lot of reasons
Every body can say this :I LOVE YOU"!!!Â
First :probably that persons do not really love you
Second :need some space to think about you
Third:that person is a cold person and does not speak a lot (her personality is like that )
Fourth :he/she is really busy
Fifth : She/her is a little shy and waits for you to start talking
and so on...
.
**in my opinion I think people "pay for their words "!! I mean don't speak a lot .!!!