Safe state will never lead to deadlock. Unsafe state may lead to a deadlock. Deadlock is subset of unsafe state.
There are states that are neither safe nor deadlocked, but which lead to deadlocked states. As an example, suppose we have four resources: tapes, plotters, scanners, and CD-ROMs, as in the text, and three processes competing for them. We could have the following situation:
Has Needs Available
A: 2 0 0 0 1 0 2 0 0 1 2 1
B: 1 0 0 0 0 1 3 1
C: 0 1 2 1 1 0 1 0
This state is not deadlocked because many actions can still occur, for example, A can still get two printers. However, if each process asks for its remaining requirements, we have a deadlock.
Ref: Andrew Tanenbaum solution manual.
Also see: https://cs.stackexchange.com/questions/45145/why-unsafe-state-not-always-cause-deadlock