Can someone people help me understand this? Like what even is a Hail Mary and how does it save them?

OKAY I GENUINELY DO NOT UNDERSTAND CATHOLICISM. I am not a hater but I just don’t understand it.

YOURE TELLING ME that my girl goes and tells some random dude that she likes me and because we’re both girls she has to say 200 Hail Marys?? And that just heals her?? Saying a chant over and over just patches everything bad she’s done?? I literally don’t get it. Someone please help me understand this.