1)
What is "Hoveh"?
1.
Rav Sadya Gaon: It is attaining.
2.
Rashi: It is gain.
3.
Ri Kara: It is benefit.
4.
Metzudas David: What good [does he get from his toil, that he is enticed to toil Tachas ha'Shamesh]? Hoveh is an expression of Havayah (existence).
2)
What is "Rayon Libo"?
1.
Rav Sadya Gaon: The desire of his heart. Ri Kara - this is like Re'us Ru'ach. Rayon is like Ratzon and Ta'avah - "Rayonach Al Mishkevach Seliku" (Daniel 2:29).
2.
Rashi: It is breakage of his heart amidst toil and worry that he toiled and will leave to others.
3.
Ibn Ezra: It is his many thoughts. An Ashir has fear and many thoughts.