Could you tell me the difference between these three sentences:
(1) I always remembered his smile.
(2) I always remembered his smile on his face.
(3) I always remembered the smile on his face.
It sounds as if the speaker is fondly thinking of times past and talking about a person who is no longer with them.
There is no context, so I may be incorrect to assume this, but I think "I will" combined with a present tense "remember" would likely be more natural. If you are writing this sentence, then you are currently remembering. I find that "Remembered" is hard to use naturally outside of "I just remembered" or "I want to be remembered".
1: His smile
I always remembered his smile.
I'll always remember his smile.
This sentence means that when you think of him, you think of those moments when he smiles at you.
2: Smile on his face
I always remembered the smile on his face.
I'll always remember the smile on his face.
This sentence is more about remembering a person as being a happy person who smiles a lot. His face is being characterized as having a smile.