What does it mean to say i always liked you completely?

Answer 1

If someone said this to you, it probably means that they really liked you a lot. I cannot tell if they liked you as just a friend or a little more just by looking at your question, but they obviously liked you a lot.

Answer 2

It means that the speaker has always had strong feelings of affection or fondness towards the listener without reservation. It implies that the feelings have been consistent and sincere over time.