My experience with NTs is they aren't good at saying how much they like or appreciate you. They DO things for you, spend time with you, talk and write to you and listen attentively. Boredom is the kiss of death for an NT, so if he/she is in a relationship with you (and you're not a relative, and even then...) it means you are appreciated and considered worthy.
An ENTP friend once told me "I'm stingy with my time [and think of how much time we spend together.]" The last part wasn't actually said, it was understood, and the whole of it was meant as a compliment.