Read 1 Samuel 18:21 Using Other Translations
And Saul said, I will give him her, that she may be a snare to him, and that the hand of the Philistines may be against him. Wherefore Saul said to David, Thou shalt this day be my son in law in the one of the twain.
Saul thought, "Let me give her to him, that she may be a snare for him and that the hand of the Philistines may be against him." Therefore Saul said to David a second time,"You shall now be my son-in-law."
“Here’s another chance to see him killed by the Philistines!” Saul said to himself. But to David he said, “Today you have a second chance to become my son-in-law!”