The literal translation of the words are: sweet is "suamalie" and heart is "fatu", so it translates to "fatusuamalie", and if you said that to someone, you will sound stupid - lol. So translating the meaning or the idea should be, "Lo'u Fatu (My Heart)" or "La'u Pele" (My Dear/Dearest).
Pele (dear), Fatu (heart). The literal translation for sweetheart is: suamalie (sweet) heart (fatu). So translating the idea would be to use such endearments such as Pele and Fatu.
Manamea
My sweetheart - la'u pele, la'u manamea.
Ou te alofa ia te oe ma lo'u fatu atoa
O le ki i lo'u fatu
True love, sweet heart
Fatu o Polenisia
I totonu o lo'u fatu
In Samoan, you would say "ou te fiafia i a oe" to mean "you're sweet" in English.
a'o; a'oa'o; learn by heart - tualoto; learned - poto
O le a'a o lo'u fatu
There is no Samoan word for beutiful soul...but to something similar to it is "Lotolelei" which, translated in English means "good heart".
Fatu-Samoan translation for the English word heart
nuit doux coeur
Samoan Pride
chérie je t'aime
la'u lotomomomo. "My heart is broken" - "O lo'u fatu ua ta'e" or "Ua ta'e lo'u fatu". Lo'u is "my"; fatu is "heart"; ta'e is "broken".