If you mean "Sweetheart" in the sense of two people who are married, dating, or courting:
Geliebter (געליבטער) = male sweetheart
Geliebte (געליבטע) = female sweetheart
In general:
"Zissele" and "Ziskeit" mean "Sweetness," and "Zisseh neshomeh" means "Sweet soul," while "Neshomeleh" means something like "Dear soul"; those are all terms of endearment.
"Sweetheart" would literally be "Zisseh hartz," but that's not a term of endearment that I have ever heard.
Vugglemantis
Bubula is a Yiddish word usually used by grandmothers or older people. Bubula usually refers to children. In modern times, the word is used to reference anyone who is considered close. The meaning for this traditional Yiddish word is similar to "dear" or "sweetheart."
Yiddish = Yiddish (ייִדיש)
The Yiddish word for funny is "קומיש."
The Yiddish word for disappointed is "bafel."
The Yiddish word for swindler is "gonif".
The Yiddish word for colored is "farblondzhet."
Bling is not a Yiddish word or a Hebrew word.
The Yiddish word for grandmother is "Bubbe".
The Yiddish word for lawyer is "advokat".
The Yiddish word for trivia is "tseyneray."
The Yiddish word for love is "libe."