Where does “простосердечный” come from?

простосердечный (Russian) comes from Russian про́сто, from Russian просто́й, from Russian проста́ивать, from Russian простоять, from Russian стоя́ть, from Old East Slavic стоꙗти, from Proto-Slavic stojati, from Proto-Slavic stojěti — Creates stative verbs from perfective roots;...

простосердечный (Russian): Good-natured and sincere; heartfelt

Definitions

  1. Good-natured and sincere; heartfelt

Ancestry of “простосердечный”, step by step

простосердечный traces back through two separate lines of ancestry.

via Russian про́сто

StepLanguageWordMeaning
1Russianпро́стоsimply, plainly, just
2Russianпросто́йsimple; ordinary
3Russianпроста́иватьto stand, to stay for some time
4Russianпростоятьto stand, to stay; to stand idle; to stand, to...
5Russianстоя́тьto stand
6Old East Slavicстоꙗтиto stand
7Proto-Slavicstojatito stand
8Proto-Slavicstojěti
9Proto-Slavic-ětiInherited, stative; Deadjectival, inchoative;...
10Proto-Balto-Slavic-ēˀtei
11Proto-Indo-European-éh₁tiCreates stative verbs from perfective roots;...

via Russian се́рдце

StepLanguageWordMeaning
1Russianсе́рдцеheart
2Old East Slavicсьрдьцеheart
3Proto-Slavicsьrdьceheart
4Proto-Balto-Slavicśirˀdísheart
5Proto-Indo-Europeanḱḗrheart
Every word from Proto-Indo-European -éh₁tiEvery word from Proto-Slavic -ětiEvery word from Proto-Slavic stojěti