How do I know if she really likes me?

well, from what I understood, the friend told you she likes you? If that’s the case, it’s a pretty safe bet it’s true. Girls may seem like they’re good at keeping secrets, but they always need to tell at least one person. Any indications that she likes you; when she’s watching you play guitar hero, glance up at her. If she’s smiling at you, and giving you all her attention, she likes you, and if she doesn’t look away when you do look up, if means she’s not afraid for you to know. If she blushes and looks away, she still likes you, but she’s shy. If you notice she talks about other guys that might mean she’s bored, if she’s crazy about you, she’ll either keep asking you questions about yourself or make a focus on you [unless she’s the type on talks about herself.] another sure sign, is if she touches you. Give her opennings, like if your walking side by side, slowly walk closer to her, brush your hand on hers. If you’re sitting next to each other, have your knees touching. if she pulls away, or moves her hand/knee that probably means she’s not into you, if she doesn’t though, maybe try holding her hand, or sliding her hand onto her leg. Good luck :)