How many letters does the top answer for “tendency to believe too readily and therefore to be easily deceived” have?

The most common answer is credulousness (13 letters).

Crossword clue: tendency to believe too readily and therefore to be easily deceived

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

credulousness 13 letters wn-def

tendency to believe too readily and therefore to be easily deceived

gullibility 11 letters wn-def

tendency to believe too readily and therefore to be easily deceived