Moses gives two reasons for G-d's choice of Yisrael:
He found them worthy of His love, and because of His oath to their Patriarchs.
The reason for His love is not given, but it may be because He knew Yisrael's faithfulness would be unswerving." - Ramban
"One who serves out of love is ready to make great sacrifices for the object of His affection" - Rashi/Rambam
"Meditate on G-d's great and wondrous deeds and creations through Torah and seek His incomparable and infinite wisdom, this will lead to love and appreciation of Him and a desire to know Him more." - based on Rambam
For centuries, the Jewish people made extraordinary sacrifices to remain faithful to the Creator.
That unswerving loyalty reveals a deep love, sometimes consciously felt, and sometimes hidden beneath faith, awe, and commitment.
"It is natural to choose a friend that will remain loyal no matter how great the difficulty" - Ramban
Explore the NextSelf Blog. Start with this post explaining the world of souls. And my Youtube.
The blog lists all the difference patterns to study, understanding patterns is how one can develop 'Daas' [felt knowing].
Update: As awe, trust, and love deepen, they can allow greater openness and intimacy with the Creator. That intimacy can include sadness when you notice how much more of His goodness can be revealed.