Dear Rabbi, It is taught that Mashiach will come when Klal Yisrael does teshuvah. This doesn’t seem realistic, do the Rabbis actually think that all of Israel will do Teshuvah? There are too many Jews (Thank G-d) and most are secular. Will Mashiach ever come?
Maimonides teaches that the repentance of Israel is promised by the Torah (Hilchot Teshuva 7 5)- nothing can be more certain than that. The Mashiach will definitely come - it is one of the 13 principles of faith. There are too few Jews- definitely not too many. The question each of us should be asking himself is not whether G-d will fulfill His promises- of that there is no question- but whether as a Jew he is doing enough good for the Jewish People to help speed redemption along.