How do the opening words of the vow reveal Jephthah’s heart?

In spite of Jephthah’s seemingly brimming confidence in public, right down to his final declaration to the Ammonites, The Lord, the Judge, decide this day between the people of Israel and the people of Ammon (Judges 11:27), and in spite his being filled with the Spirit, Jephthah’s subsequent utterance of a vow gives the picture of a man still struggling with insecurity.¹ In the original he uses an emphatic infinitive, saying, If you will indeed give. This gives voice to his internal angst. He wonders whether the Lord will after all, reject him, too. He has everything to lose if the battle goes against him, including his position in his clan and tribe, which meant much to him. If he loses, he will be an outcast again. And that simply cannot happen.²