Dear Sister,
There are two sorts of persons in the world. The one — strong-nerved, quiet, yielding to nature, not given to much imagination, yet good, kind, sweet, etc. For such is this world; they alone are born to be happy. There are others again with high-strung nerves, tremendously imaginative, with intense feeling, always going high one moment and coming down the next. For them there is no happiness. The first class will have almost an even tenor of happiness; the last will have to run between ecstasy and misery. But of these alone what we call geniuses are made. There is some truth in the recent theory that "genius is a sort madness".
Now, persons of this class if they want to be great, they must fight to finish — clear out the deck for battle. No encumbrance — no marriage, no children, no undue attachment to anything except the one idea, and live and die for that. I am a person of this sort. I have taken up the one idea of "Vedanta" and I have "cleared the deck for action". You and Isabelle are made of this metal; but let me tell you, though it is hard, you are spoiling your lives in vain. Either take up one idea, clear the deck, and to it dedicate the life; or be contented and practical; lower the ideal, marry, and have a happy life. Either "Bhoga" or "Yoga" — either enjoy this life, or give up and be a Yogi; none can have both in one. Now or never, select quick. "He who is very particular gets nothing", says the proverb. Now sincerely and really and for ever determine to "clear the deck for fight", take up anything, philosophy or science or religion or literature, and let that be your God for the rest of your life. Achieve happiness or achieve greatness.
Ever your loving brother,
Vivekananda.