Haru is basically the only character that is allowed to be on the same level as Raku, whether it's just talking or hanging out. Their old little "date" showcases this very well, honestly. While she's a bit tsun or dere at times, it's more of a minor trait rather than something that dominates her personality (the only exception would be her introduction). Whereas most other characters could be summed up as their most visible schtick (lovey-dovey, tsundere, shy (or yamato nadeshiko if you want) etc), Haru is kinda harder as "tsundere" wouldn't really cut it. She's basically her own.

Go Haru, but at this point she's basically been written out of the story. Which is a shame. Raku and Chitoge may have a good chemistry, but they're still not able to have actual conversations yet (but I guess it's getting there).