Well , I can't see the wind, However I know it clearly exists . Nor can I see love... I know that exists As well , ,,,, I can't see methane .... However if you have ever been on a crowded elevator - we all can tell When that's present !
no, seeing is not always believing.. you can doubt about what you see, but when you believe you know what you see..when you believe is better to see not when you not believe to see.. example you see something from Jesus but don't believe, it is worse than to believe and not to see.
Seeing is not always believing. we have never seen cell phones electromagnetic waves, but all of us believe in it because cell phones are working. we have never seen the big bang happening, but many still believe in it because we see the impact of it. we have never seen God. but few of us believe in him because they have seen his creation and creativity.