Why was it from Hashem that a Shofet of Yisrael marry a Nochris?
Radak (13:4): Surely he converted her, and did not transgress the severe Isur "v'Lo Sischaten Bam" which leads to denial of Hashem "Ki Yasir Es Bincha me'Acharai" (Devarim 7:3, 4). The verses do not say that he was punished for this 1 , or that he did evil in Hashem's eyes, and Hashem gave him success in everything! Yisraelim in that generation did not fear Hashem enough to merit a full salvation. The 40 years of Pelishti subjugation (verse 1) include the 20 years of Shimshon's rule. Yisrael were not fighting Pelishtim, only Shimshon was; he was living among them. They did not have a reason to fight Yisrael; also, they feared Shimshon. Yisrael handed him over to the Pelishtim (15:11-13).
Malbim: Refer to 14:4:3:1.
Radak: He was punished for "Hi Yesharah b'Einai" (verse 3) - he desired her beauty, and also desired the other wives that he took. Initially he intended for Hashem's will (a pretext to afflict the Pelishtim), but physical desire became mixed with this, and he was punished [through his eyes] Midah k'Neged Midah. (Shitah Mekubetzes Sotah 9b, citing Tosfos ha?Rosh, says that she did not convert. How can he reject Radak's proofs? - PF)
What is the meaning of "To'enah"?
Rashi: It is a pretext to quarrel with [the Pelishtim]. Radak - this is like "veha'Elokim Inah l'Yado" (Shemos 21:13). Also Targum Yonasan says so; it is like the Targum of "Alilos Devarim" (Devarim 22:14).
Why does it say that then, the Pelishtim ruled over Yisrael? It already said so (13:1)!
Malbim: This is why Hashem arranged that he marry a Pelishti woman, so they will think that his hatred is due to marriage, and not due to his pain over the subjugation of his Yisrael brothers. Had they know the truth, they would have afflicted Yisrael amidst their anger.
