PLEASE HELP ME; WORRIED!!?

Ok so my friend's older sis (shes 22 im 12) was chatting with me last night and she said my bf said that he also likes this other girl. I confronted him about it and he said "No, I like you and only you. You're my Yoko Ono to my John Lennon." He also explained why he told his friend he liked that girl. It was awhile ago, right before he liked me and he only said it to get his friend off his back, and he said hes never liked her more than a friend. Do you think hes telling the truth or lying?!?!