The difference is in how the person propels the object. If a person kinda grabs an object with their cupped hand and pushes the object forward with intention to reach a specific place, it's a throw. If the person lazily grabs the object and snaps it away like a frisbee, without any care about how far away it lands or where it lands, it's a fling. A fling can also refer to an angry, uncalculated throw OR an unexpected movement (or, in slang English, a short, passionate relationship). However, they're so closely related that people would typically just say "throw" for all of these situations, and any sentence you could say "fling" in would just as easily use "throw", so don't worry too much about the distinction when speaking.

The difference is in how the person propels the object. If a person kinda grabs an object with their cupped hand and pushes the object forward with intention to reach a specific place, it's a throw. If the person lazily grabs the object and snaps it away like a frisbee, without any care about how far away it lands or where it lands, it's a fling. A fling can also refer to an angry, uncalculated throw OR an unexpected movement (or, in slang English, a short, passionate relationship). However, they're so closely related that people would typically just say "throw" for all of these situations, and any sentence you could say "fling" in would just as easily use "throw", so don't worry too much about the distinction when speaking.

fling is in a sense the same as throw but fling is throwing with force or throwing something unexpectedly i.e. she suddenly flung an apple at him.