[verb stem (ます-stem)] + そうにない
Variant: [verb stem] + そうもない / そうにもない
そうもない and そうにない are used to express that something is very unlikely to happen or shows no signs of happening. They are the emphatic negative forms of the verb-stem + そうだ pattern (which expresses that something looks like it will happen).
Attach そうもない or そうにない to the verb stem (masu-stem):
Both forms convey the same core meaning, but そうもない is slightly stronger and more emphatic than そうにない because of the particle も, which adds a sense of "not even" – as if to say there isn't even a hint of the action happening.
Be careful not to confuse this pattern with V[stem] + なさそう, which describes the appearance of something not being the case (e.g., ふら降らなさそう – "it doesn't look like it will rain"). In contrast, そうもない / そうにない emphasizes that there is little to no possibility of something happening, often with a sense of frustration or resignation.
For polite speech, use そうもありません or そうにありません.