What is love?
Do you know what love is?
Are you in love?
Have you ever been in love?
If you have other know any of these things than you're most likely wrong. Emma Swan thought she knew what love was and that she had been in love before until she met Killian Jones, when she met him, she knew she was wrong.
Emma Swan works as a FBI BAU agent, and Killian works as a detective a floor down from hers, that's how she met Killian.
When Emma met Killian she didn't know how her feelings would reacted. When she finally got close to him, she knew her feelings were there but she tried to ignore them, and than she realized she couldn't. Emma also had a boyfriend and Killian has a girlfriend, but she couldn't stop what she felt.
Emma wanted to know what Killian felt, but at the same time she didn't want to because if he didn't feel the same way than she didn't want to know. Her boyfriend was an ass hole but she couldn't leave him or he will kill her.