The riddle proved to be impossible to solve. That's when the 30 men resorted to extortion. They threatened Samson's new Philistine wife to draw out the solution from her new husband or else they would kill her and her entire family. And after numerous passive-aggressive attempts from his wife, Samson eventually caved and told her the secret. 

Why did Samson reveal the answer to his riddle? Judges 14:17 states that it was because she "pressed him hard." The Hebrew verb means "to be constrained." In other words, figuratively speaking, she "squeezed" the answer out of him. It is interesting to compare this word to how nonbelievers view Christianity. They contend that religion is constraining. We can't do this. We mustn't do that. But what they don't understand is that constraint (in truth) is actually the means to liberation. Consider the example of playing the piano. Sure, I can bang away on the keys, pressing whatever note I please. But for a more beautiful composition, I must constrain myself to a musical scale. The same is true of God: he is truth and his law leads us to the fullness of human life.