What does the cryptic crossword clue "A belief's becoming shaky? That's likely (8)" mean?

The definition is "likely". The wordplay uses an anagram. anagram of A + BELIEF'S = FEASIBLE; definition: "likely" The answer is FEASIBLE.

A belief's becoming shaky? That's likely (8)

Daily Mail Cryptic #17052 | 21 Across | 2023-03-13 flower