If anything recent elections have told us that you can't be sure of anything. I think she will actually reduce her majority.
I also would caution writing off labour as corbyn's socialist agenda will probably be looking better than what the Tories are currently doing to the country to some.
The lib dems are also going to make gains from pro-eu supporters with very short memories.
If we had a party that worked for the people as they should then all the above would be out.
p.s. I didn't forget UKIP, I just think they are a bunch of snobby racist clowns.