Hi Vili (@AlphaOmega)! Thanks for this question! You obviously care for this sister in Christ a great deal.
I agree with what @Luna said. Although truth is important, at this stage it is equally important for this sister in Christ to know that you are sincere in your love and care for her when you begin sharing biblical truths with her. It is also important that these truths are communicated with gentleness and respect.
One way to start such a conversation would simply be to ask her some questions about her understanding of biblical truth - motivated by genuine curiosity.
I wasn’t familiar with the Word of Faith Movement, so I did some research. Please, somebody, correct me if I’m wrong, but this movement sounds like it may not be based on scripture. If this is the case, it may very well be that this dear sister is unaware of biblical truths as compared with ideas which have been taught through this movement. She may see them as one and the same.
May God grant you wisdom as you engage this sister and witness the truth to her in love. God bless you Vili!