Ananias had plenty of doubts (obviously) about Jesus’ ideas concerning his going to Saul and being used to restore Saul’s sight. He knew from plenty of reliable sources about Saul’s evil track record. He also knew what Saul’s intentions were for him and the other saints in Damascus. Serving as an “accomplice” to any of that didn’t suit Ananias at all. And he likely didn’t see the sense in being the first Christian within the persecutor’s range when he could see again. It seems Ananias fully intended to use his God-given wisdom to avoid compromising the security of the church in Damascus.
Source: Panting, Saul — From Persecutor to Preacher, “Applying God’s Word to Me”
