To give you a more precise answer, I need to know:
* Who is being suspected? Is it Hamlet's sanity? Is it Claudius's guilt? Is it someone else entirely?
* What is the context of the lines you're looking for? Are you interested in lines spoken directly about suspects, or lines that allude to suspicion more subtly?
Once you tell me more about what you're looking for, I can provide specific examples from Act III of Hamlet.
For example, here are some possibilities:
* Suspecting Claudius:
* "To be, or not to be, that is the question: / Whether 'tis nobler in the mind to suffer / The slings and arrows of outrageous fortune, / Or to take arms against a sea of troubles, / And by opposing end them?" (III.i.55-58) Hamlet's famous soliloquy could be interpreted as expressing his suspicion of Claudius and his desire to act against him.
* "The play's the thing / Wherein I'll catch the conscience of the King." (III.ii.20-21) This line explicitly reveals Hamlet's plan to use a play to expose Claudius's guilt.
* Suspecting Hamlet:
* "O, my offence is rank, it smells to heaven; / It hath the primal eldest curse upon't, / A brother's murder." (III.iii.36-38) Claudius's soliloquy suggests he suspects Hamlet knows of his crime and is seeking revenge.
* "Madness in great ones must not unwatched go." (III.i.169) Polonius, believing Hamlet's madness is caused by Ophelia's rejection, uses this line to justify his suspicion of Hamlet.
Let me know what kind of suspicion you are looking for, and I can help you find the right lines!