Yes, you can fake a relationship but this is not a good thing to try. Faking a relationship is not good and it is unfair to your partner, you would be playing with someone else's emotions. No matter how long you are able to manage a fake relationship, the truth will catch up with it sooner or later and you will be leaving some one else heart broken.
This has happened to many people and a lot of them are finding it difficult to get into another relationship.
Fake relationship is also not good for you, you will be putting yourself into unnecessary stress.
Yes, you can fake a relationship. However, it is always about time that the truth comes out. Your true emotions can never be replaced with fake ones. Slowly, you will grow tired of faking it. A point will come when coming out clean will be a much more appealing choice than continuing to fake your relation further.
Moreover, faking a relationship is toxic for your mind and heart as well. You are also being unfair to your partner who could be in love with you with a whole heart. Not telling him or her about your true feelings is cheating and much crueler than actually breaking up.