How sound is it to think well of Allah regarding His answering prayers despite many sins? And what is the legal limit for trimming nails?

Repentance, sincere and true, is obligatory for sins. Asking for forgiveness without repentance leaves forgiveness contingent upon Allah's will. Increasing good deeds is praiseworthy, and it is hoped that they will expiate sins, for "Indeed, good deeds do away with ill deeds." However, one must beware of persisting in acts of disobedience, as they can destroy a person, and what is considered minor might be significant in the sight of Allah. One must strive in supplication with certainty of its acceptance, knowing that the answer might be a reward stored for the hereafter or the aversion of evil. As for fingernails, it is recommended to trim what extends beyond the fingertip for aesthetic and hygienic purposes, and to facilitate ritual purification.