谢谢你的关心

“谢谢你的关心，谢谢你的关怀”这两个比较好，“谢谢你的关注”这个就比较少了，“谢谢你的心事”这个句子没有人这么说

I also think "关心“is better, but it often not be used offen as it's a little offical, you may also say："谢谢你关心我。in Chinese we use verb more often than noun, as our teacher told us. :P

a slight digression, if saying good-bye to ex boy friend : " 謝謝你的愛 " " 謝謝你曾經給我的愛 "

l think both 关心 and 关注 are right. But they're used in different situation. If someone cares for you, you can say 谢谢你的关心。 If someone pays attention to you, like he follows you on italki. You can say 谢谢你的关注。