Possible meaning are 1) the Israelites considered doves to be gentle and soft birds, and the man considers the woman's eyes beautiful because the way the woman looks at him makes him think she is gentle. AT: "you are very gentle" or 2) the man is speaking of the woman's white eyeballs or the shape of her eyes as being like the shape of a dove. (See: [[rc://en/ta/man/translate/figs-metonymy]])