In what way "I am better to you than 10 sons"?
Rashi: I endear your more than I do Peninah, who bore 10 sons.
Radak citing Targum Yonasan: My love for you is better than 10 sons. Verses often say 10 (or seven), and it is not precise, e.g. "v'Afu Eser Nashim" (Vayikra 26:26), "me'Asarah Shalitim" (Koheles 7:19), "Sheva k'Chatoseichem 1 " (Vayikra 26:21), "Sheva Yipol Tzadik" (Mishlei 24:16).
Radak: Mo love for you is more than for my 10 sons from Peninah.
Malbim: Even if you despaired of bearing children, you need not be sad. You are not commanded about Peru u'Rvu. If you are concerned for support in your old age and who will bury you, I can help and protect you! 2