1)
What should Hashem remember?
1.
Rashi: The matter that You made me hope for, via Nasan ha'Navi.
2)
What is the meaning of "Yichaltani"?
1.
Radak: You told me to hope to You.
2.
Malbim: I do not hope for it like a matter that is not clear (such hope is Tikvah), rather, like one who hopes for a clear promise.