Smallville, Episode 2.16: Chloe and ClarkClark drops off raffle items at the Talon in the morning, telling Pete, Lana, and Chloe that is mom is sick. When Chloe starts trying to ask questions as to what she has, he snaps at her; she apologizes and so does he saying he needs to go back to the hospital.
The next day, Lana had told Chloe that Clark had come down with the same disease. Chloe drives up to the farm, apologizing to Jonathan for being a nuisance and asking if she could sit with him*. She sits with him remarking about how he ruined his perfect attendance record. She adds in that she'd never seen him sick before and made her wonder "what if something happened to [him] and [she] never got a chance to tell..." Chloe wrote a letter to read/give to him:
I want to let you in on a secret. I'm not who you think I am. In fact, my disguise is so thin, I'm surprised you haven't seen right through me. I'm the girl of your dreams masquerading as your best friend. Sometimes I want to rip off this facade like I did at the Spring Formal, but I can't because you'll get scared and you'll run away again. So I decided that it's better to live with a lie than expose my true feelings