Complex sentence: She attempts to maintain friendships with Dave and Stoney but is often put off by their childish mannerisms, However she is already showing signs of growing tired of Matt's snobby and egotistical ways.
Split into simpler sentences: She attempts to maintain friendships with Dave and Stoney but is often put off by their childish mannerisms. She is already showing signs of growing tired of Matt's snobby and egotistical ways.