Not being able to disprove something only makes it a possibility, not a fact. If you don't have a source to confirm (prove) the connection then connecting the profiles is problematic. If false, its misinformation for others that see the connection. Other profiles (like children, grandparents etc ) that are linked to this couple, then have to be undone if its proven not true.
Best practice - Use a research notes area to explain the possible connection, add the other profile's Wikitree ID in the notes so you can keep tabs on it. Don't connect unless you come up with a reliable source.
That said, I am a little confused. You have a marriage source for the wedding of Eliza and Thomas?? Is there some reason this is in doubt?
