To: b.wielebska
Dear Basia,
You need to change the fade in and fade out area in the text editing winodw - right click on the text item on the timeline - choose Edit.
Follow the link below to find on how to edit the fade in and fade out area on the audio effects, it would be the same for text fade in and fade out, you need to reduce them to minimal:
http://onlinehelp.avs4you.com/AVS-Video-Editor/Features/EditingVideos/Audio/AudioEffects/AudioEffects.aspx
Please let me know if I can be of any further assistance to you.
Kind regards