A matter of pronounciation. Happens in both ways, especially if you expect people to use one language and they use another or even mix then, as in this case. Although, hati manis could be really used as ‘sweetheart’.
Sudah beli minuman? – Did you buy (some) drink already?
Belum, tukang* nya ada hati manis aja – Not yet, the sales guy had only sweet heart
Tukang – any kind of repairer, salesman, chef of streetfood etc
Hati – heart, in Indonesian canteens usually heart of chicken (ayam)
Hot tea manis mungkin? – Maybe sweet hot tea?