I love you to the moon and back, I love you  more than you'll ever know. But if you don't  

want to say love, you can say "I really  care about you" or "You mean a lot to me"  

or "I like you a lot".

You're really important to me.

You're my top priority.

You're the only one for me. 

But the most important lesson here is of you love  somebody, make sure they know it and feel it.