1)
Why did Sha'ul need to tell his servants to speak to David?
1.
Radak (21): Sha'ul tricked David [to nullify] the marriage to Meirav, so David retracted [from asking to marry Sha'ul's daughter].
2.
Malbim: They told him that Sha'ul did not prevent him from marrying Meirav; she did. Michal loves you, so you can marry her!
2)
What is "b'Lat'"?
1.
Radak, based on Targum Yonasan: It is covertly. He wanted it to seem that he is sincere.
