Vayne is a very good adc especially if you like playing champions like Zed, Yasuo, and basically champs with mechanics! Vayne is strong early game because of her w. Early game, adc's take a lot of damage from her w just because they are very squishy! Her late game is very strong because that is when she gets a lot of attack speed, her q is on a 1.5 - 2.0 sec cool down and since her w doesn't have a cooldown like vi's w it will be OP as heck just because it synergizes well with her attack speed.

Well when you looked at the items you probably wondered why Trinity Force? You should get trinity force because it gives you all the things you need as Vayne. For example, it gives you a sheen proc which makes you basic attack deal bonus damage after you use an ability so in the late game when you spam your q you will deal TONS OF DAMAGE, it gives you attack speed which helps with her w, and a more chance of you having crits which helps you kill your enemies faster. Trinity Force also has a special passive where when you basic attack someone you get increased movement speed which will help you chase down your enemies.

In the late game if you are winning lane and your good at Vayne, expect you to be able to kill enemies in seconds! You'll have lots of attack damage and attack speed which helps with the lifesteal your geting. You'll be able to out play your enemies because of the movement speed and since your q will be on a low cool down you will be able to kite them. If your absolutely a god at Vayne expect to carry your team since you'll be close to unkillable!
I hope you love this build, the one and only Crs Piglet uses it!