I feel that you do have to go slow with this one, especially as the sep as been for so long. May suggest she go on a month to month lease if she can and start to date and such, before taking that full leap. I can completely understand the need to be sure her feelings are true, but ulimately you are the only one that can be sure of that.
Me - 44 H - 44 M - 19yrs together - 23yrs D16 S8 EA/PA - Bomb Oct20/06 Jan 8/07 Feb 01/07 Jul 15/07 H still @ home Recovered!