I think that he's fake and that he's lying to me.?

Well my "bestie" guy friend and i have been texting.. He tells me the sweetest things ever, like "You're an amazing friend..I love you (a lot)...I'll always care about you..I love you more than you love me.." Well i recently found out that he's been texting some similar things to my best friend, who he seldom talks to..He said "i love you." I told him that he's a liar, and no he doesn't. He said "i do, trust me." I said "Why?" He said "Because you're an amazing friend" I said "I hope you don't say that to all the girls you text" He said "I don't, I am a flirt, but i rarely mean it as much when i say it to you." I know he's lying to me, but i can't get over the fact that he's said some deep things to me. I tried accusing him last night, but it really left me with no answers. I just can't believe that he's a lying a**hole. My friends have told me not to believe him because he's and jerk and will hurt me.. What should i do?