Swearing does not break Wudu
Some people think that swearing or laughing out loud breaks Wudu, so this thought is wrong. However, it is recommended (Mustahab) to perform Wudu after swearing, backbiting, or reciting any bad poetry, etc. Yes, laughing out loud (Qahqaha) during a prayer that involves Ruku and Sajdah does break the Wudu. (Aham Masail / Vol: 2 / Pg: 56)