ISTG stands for "I swear to god." It is a text abbreviation. It is used to emphasize a statement. "ISTG, I did not eat your leftovers." It is a pledge. It is a promise. It is also a threat. "ISTG, if you do that again..." The tone decides. It can be serious. It can be playful. It can be exasperated.

ISTG is common in texting and social media. It is a way to say, "I am telling the truth." It invokes a higher power. It adds weight. It is not formal. It is not for a job interview. It is for friends, for arguments, for moments when you need to be believed.

Related abbreviations

• ISTH: I swear to hell, a variant.
• TBH: to be honest.
• FR: for real.
• NGL: not gonna lie.

ISTG is a small oath. It is a way to say, "I am serious." In a world of lies and jokes, it is a signal. It says, "This one is true." That is a valuable thing. It is also a common thing. Everyone wants to be believed. ISTG is a tool for that. Use it wisely.