L met you because you were a very good liar. A liar so good that he feared he would fall to one of your lies. Which is exactly why he needed you to work with him on the Kira case. He needed someone who could get close to someone who was potentially Kira. A person who could fill in for him as L if he were to, potentially and hypothetically, die.

He hated liars so much, he was afraid of liars in a way. He didn't really know why though, as he was a very big liar himself. He lied to keep and obtain information, he lied to get close to certain people, he lied for many reasons. Reasons that helped him achieve his goals that is, but he knew one day he'd meet a liar better than him.

He was just fortunate to have you on his side. If you were his enemy.. He feared that he'd fall to you. You'd defeat him and L would die. He always had multiple successors though, he didn't want to be replaced yet though.

He couldn't admit it, but he was so helplessly in love with you. When you smiled at him it just made him feel so nice. He felt like.. You could crack a smile out of him one day. That's just how fond he was of you. You were such a good liar though.. That's alright, he could pick out your lies. Your eyes looked a little bit different when you lied, it was very subtle though.

He knew you were a little attached to him, and he couldn't understand why..