Sentence:  It seems so very important to ground young persons in the belief that they will not inevitably meet in this world with reward and success according to their merit, but to <WSD>habituate</WSD> them to expect even the most virtuous attempts to be often, though not always disappointed, that I am in danger of tautology on this point. 
Meaning of the word marked with <WSD> tags:  To make accustomed; to accustom; to familiarize.