I'll give it a shot just to kick this off, because I know there must be better ways to say it, but here goes...
More colloquial:
對於未來，我冇害怕，因為我心淨係有愛
More literary:
對於未來，我毋害怕，因為我心只有愛
However, this is more along the lines of:
For the future, I have no fear, as my heart has only love
If you wanted to specifically involve the person you're writing this to (but that might not be your intention), then it could be:
對於我們的未來，我毋害怕，因為我心對你只有愛
Which is more along the lines of:
As for our future, I have no fear, as my heart has only love for you
(More for written than colloquial)
More colloquial:
對於未來，我冇害怕，因為我心淨係有愛
More literary:
對於未來，我毋害怕，因為我心只有愛
However, this is more along the lines of:
For the future, I have no fear, as my heart has only love
If you wanted to specifically involve the person you're writing this to (but that might not be your intention), then it could be:
對於我們的未來，我毋害怕，因為我心對你只有愛
Which is more along the lines of:
As for our future, I have no fear, as my heart has only love for you
(More for written than colloquial)