Looking for a single word

I am looking for a word that describes someone who says something to you but when talking to someone else says the complete opposite.

For example: if someone said they loved a color of a vehicle but when talking to others they say they hated it.

Solution 1:

A person who expresses one thing to one person and the opposite to another is two-faced.

2. figurative. Deceitful, insincere: = double-faced adj.

1864 in J. H. Newman Apol. v. 429 Two-faced persons, who did not go simply and straightforwardly to work.

Oxford English Dictionary

BGT judge branded 'two-faced' by Piers Morgan

Daily Express 23 November 2019

Solution 2:

I think, the most appropriate word to describe such person will be hypocrite:

a person who pretends to be what he is not

Also good word will be phoney:

an insincere or pretentious person, a fake

You can also look for some translations here and here.

And finally, you can use an idiom: say something behind someone's back.