How do I convince my wife that I love her?

my wife & I got married at 18 9 years later she's drifted awayfeom me days I did the marines for 4 years then college then focussed on getting new job... I didn't realizewhat I was doing go her and now she's talking about divorce this has made me see itall clearly and now I know what I should have been doing and that j love hermore than anything on this earth and want to make up for the years but I'm afraid she doesn't believe I'm sincere.... What do I do??? I'm lost