"Today is the day that we've been a year together
I'm hoping that this love lasts 4 ever"

"4" should be spelled out "for"

"One year of happiness
One year of sadness
One year of joyness"

Okay first off, this poem is extremely repetitive and does not catch my eye whatsoever. Also, having the title as "One Year" and then repeating it in every line, just makes the poem drag on and on, it really didn't appeal to me at all.

My advice to you would be to definetly not strat of every line with "One year..."
Instead of this:

"One year of kissing
One year of hugging
One year of holding"

Try this, just my opinion though:

"One year of passionately kissing,
Memories of your warm arms hugging me,
Holding and comforting my soul, all night long"

Or something like that because basically all you're changing in each line is one word, you are not being descriptive at all, or putting any emotion/feeling into this piece. Just write straight from your heart, if your true love really means so much to you, write everything about them, and describe everything, instead of just saying simple little things....Please take into consideration my advice, and I would go back and look over this piece...Take care and have a Merry Christamas!