This is the meaning of what is written (Bereishis 29:33): “For Hashem has heard that I was disliked,”
The simple meaning, as explained earlier in the maamar, is that Leah was thanking Hashem for giving her a son, because now her husband will love her more. In the literal meaning, “כִּּי ש ָּמַע ה'” means “for Hashem has heard,” and “כִּּי ש ְנוּאָּה אָּנ כִּי ” means “that I was disliked.”
The Alter Rebbe is interpreting the phrase “כִּּי ש ָּמַע ה'” to mean “for Hashem has caused me to hear,” and “כִּּי ש ְנוּאָּה אָּנ כִּי” to mean “because I despise myself.” I.e., because I humble myself towards Hashem, Hashem causes me to “hear” Him and come to truly fear Him, as the Alter Rebbe will continue to explain.