This past few nights i noticed that my wife feels so tired . Every time I ask her if she's okay she always answers me that she's fine .Im worried about her, what would I do to help her get into it?

Ladies are complicated and doesn't answer much when asked, honestly. They would want to see more actions rather than words. It's true what Dazzle Sy said that you may help her out by taking off some of her loads. I also suggest you take her out on a date with JUST the two of you to shake off any tension so she can open up.