shoujo?

yup! i think the twin siblings's new life is one of them.

Yeah! Transmigrating as the emperor's daughter... or the likes. They're pretty popular nowadays along with being the hero/villain's mother or something.

http://www.mangago.zone/read-manga/the_reason_why_raeliana_ended_up_at_the_duke_s_mansion/
http://www.mangago.zone/read-manga/the_reason_why_raeliana_ended_up_at_the_duke_s_mansion/
http://www.mangago.zone/read-manga/doctor_elise/?X0wO
http://www.mangago.zone/read-manga/reminiscence_adonis/

http://www.mangago.zone/read-manga http://www.mangago.zone/read-manga/the_temptation_of_a_cat_demon/

http://www.mangago.zone/read-manga/akatsuki_no_yona/
http://www.mangago.zone/read-manga/doctor_elise/?teio
http://www.mangago.zone/read-manga/namaikizakari/
http://www.mangago.zone/read-manga/hananoi_kun_to_koi_no_yamai/
http://www.mangago.zone/read-manga/ookami_shoujo_to_kuro_ouji/

MY FAVOURITE LOVE STORY EVER:

http://www.mangago.zone/read-manga/say_i_love_you/

http://www.mangago.zone/read-manga/akagami_no_shirayukihime/

http://www.mangago.zone/read-manga/dengeki_daisy/
http://www.mangago.zone/read-manga/it_s_difficult_to_love_an_otaku/
——————————
http://www.mangago.zone/read-manga/the_maid_and_the_vampire/.

Nop not all shojos are romance, I came across several non-romantic one but for some reason almost none come to my mind... apart from this one : http://www.mangago.zone/read-manga/kakei_no_alice/ -> it’s pretty similar to a Seinen (and really good by the way), with a female mc. There is a bit of romance at some point but it’s the same amount you could find in shonen / Seinen.

Your question is also valid for any genre. For example you can find some 100% romance fiction in non-shojo magazines. For example, « love is a war » (also an anime) is a Seinen (being sold in a Seinen magazine)